Entity - Detached Duplex, Bungalow and Apartment Block
Entity - Detached Duplex, Bungalow and Apartment Block
Substructure refers to the part of a building or structure that is constructed below ground level. It includes all components and systems that support the superstructure (the part of the building above ground) and transfer loads from the superstructure to the ground. The primary functions of the substructure are to provide a stable foundation for the building and to resist various loads, including the weight of the building, occupants, and environmental forces.
1.1 Excavation and Fillings
Excavation involves removing earth to create a foundation pit. This is done to reach the desired depth and shape necessary for the building's foundation. Fillings follow, adding and compacting material like soil or gravel into the excavated area to create a stable base. Both processes are essential for establishing a solid and secure foundation for the building.
1.1.1 Site Clearance - Vegetation
Site clearance in the foundation stage of building construction involves removing vegetation, debris, and existing structures to prepare the site for excavation. This includes demolishing old buildings, clearing trees and shrubs, and removing any underground utilities. Site clearance ensures a clean and safe area for construction activities to commence. Additionally, it allows for proper access and layout of the construction site according to architectural and engineering plans. Site clearance sets the stage for the foundation work to begin efficiently.
Assumptions:
The task is to clear a plot of land for construction, the total area of land that needs to be cleared in this scenario 200 square metres.
One unskilled help can clear 20 square metres per day. This involves removing vegetation on the land.
The daily wage for the unskilled help is ₦3,000.00.
Calculations:
The rate per square metre of the unskilled help is calculated as: ₦3,000.00 / 20 square metres = ₦150.00 square metres.
To clear 200 square metres, we need to calculate how many days the unskilled help will work: 200 square metres / 20 square metres per day = 10 days.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily wage: 10 days x ₦3,000.00 per day = ₦30,000.00.
Schedule of Site Clearance:
Assumed quantities: 200 square metres
Daily output per unskilled help: 20 square metres
Number of days required: 10 days
Daily wage per unskilled help: ₦3,000.00
Total cost for service or labour: ₦30,000.00
Built up rate for labour: ₦150.00 per square metres
1.1.2 Topsoil Excavation
Topsoil excavation in the foundation stage of building construction involves removing the uppermost soil layer, which is rich in organic material and unsuitable for supporting structural loads. This process ensures a stable base for the foundation by eliminating potential settlement and instability caused by the organic content. Excavation typically reaches a depth where the soil is more compact and capable of bearing the structure's weight. The removed topsoil can be stored and reused for landscaping purposes. Properly executed topsoil excavation is critical for establishing a solid, reliable foundation and preventing future structural issues.
Assumptions:
The task is to determine the volume of earth that needs to be excavated, we have to excavate a depth of 0.175 metres of a 200 square metres area of land. The result will get you 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the Unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help is ₦2,200.00
Calculations:
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days.
The unit rate is the total cost divided by the service output. That is ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00.
Schedule of Topsoil Excavation:
Assumed Quantities: 35 cubic metres
Daily output per unskilled help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
1.1.3 Trench Excavation
Trench excavation involves digging narrow, elongated depressions in the ground to prepare for foundation footings, utility lines, and drainage systems. This process requires precise measurements and careful planning to ensure proper depth, width, and alignment. Excavated soil is typically stored nearby for backfilling. Safety measures, like trench shoring or shielding, are essential to prevent collapses and protect workers. Once the trench is prepared, it serves as a stable base for laying the building's foundation elements, ensuring structural integrity and proper support for the overall construction.
Assumptions:
The task is to determine the volume of earth soil in the trench that needs to be excavated. For example, let's say you need to excavate a trench of with a total volume of 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help, including tools, is ₦2,200.00
Calculations:
Each day, the unskilled help will have an output of work 3.5 cubic metres of earth.
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00
Schedule of Trench Excavation:
Assumed quantities to excavate: 35 cubic metres
Daily output per unskilled Help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
1.1.4 Pour Backfill to Trench Excavation
In the foundation stage of building construction, pouring backfill into trench excavations involves refilling and compacting the void left after excavation with suitable materials like soil or gravel. This serves to provide support to the foundation, enhancing its stability and preventing settlement. Backfilling also helps in improving drainage around the foundation and protects against soil erosion. Proper compaction of the backfill material is essential to ensure uniform support and minimize future settlement.
Assumptions:
The task is to determine the volume of earth that needs to be backfilled to the sides of excavation For example, let's say you need to backfill 40 cubic metres.
Calculations:
One unskilled help can backfill 4 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help is ₦2,200.
To backfill 40 cubic metres, calculate how many days the unskilled help will need: 40 cubic metres / 4 cubic metres per day = 10 days
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000
Cost per cubic metre is ₦22,000/40 cubic metres = ₦550 per cubic metres.
Schedule for Pouring Backfill to Trench Excavation:
Assumed quantities to backfill: 40 cubic metres
Daily output per unskilled help: 4 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost per day: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦550 per cubic metre
1.1.5 Disposal (On-Site)
On-site disposal in building construction involves managing and disposing of excavated soil, debris, or waste materials within the construction site itself. This process requires designated areas for temporary storage, sorting, and proper disposal methods, such as recycling or landfilling. On-site disposal helps minimize transportation costs and environmental impact by reducing the need for off-site hauling. Effective on-site disposal practices contribute to efficient project management and sustainable construction practices, ensuring responsible waste management throughout the building process.
Assumptions:
The task is to determine the volume of excavated materials that needs to be disposed to a spoil heap 1 metre away, assuming the volume of excavated material is 20 cubic metres.
Disposal volume: Workers can handle 4 cubic metres of disposal per day.
Service Cost: It costs ₦2,200.00 for the unskilled help each day.
Calculations:
One unskilled unskilled help can backfill 4 cubic metres per day.
Unit rate: To find the unit rate per cubic metre, divide the total cost by the labour output: ₦2,200 / 4 cubic metres = ₦550 per cubic metres.
To dispose of 20 cubic metres, calculate how many days the unskilled unskilled help will need: 20 cubic metres / 4 cubic metres per day = 5 days.
The total cost for labour and tools over the entire period is calculated by multiplying the number of days by the daily cost: 5 days x ₦2,200 per day = ₦11,000.00.
Schedule for On-Site Disposal:
Assumed quantities to dispose: 20 cubic metres
Daily output per unskilled help: 4 cubic metres
Unskilled help wages per Day: ₦2,200.00
Total cost for service or labour: ₦11,000.00
Built up rate: ₦550 per cubic metre
1.1.6 Disposal (Off-Site)
Off-site disposal is an aspect of the construction process where excavated soil, debris, or waste materials generated during site preparation, excavation, or demolition are transported and disposed of at designated facilities away from the construction site. This involves loading the materials onto trucks or containers and transporting them to licensed disposal sites or recycling facilities. Off-site disposal ensures proper waste management, environmental protection, and compliance with regulations. It also helps maintain a clean and safe construction site, minimizing environmental impact and ensuring the efficient progress of the construction project.
Assumptions:
The task is to determine the volume of excavated materials that need to be disposed of. For example, let's say you need to dispose of 10 cubic metres of excavated earth.
One Unskilled help can load the disposal of 3.82 cubic metres per day averagely.
A 5 tonne Truck can transport 3.82 cubic metres of excavated materials per trip within a 5km radius. The transportation cost per lorry is ₦25,000.00.
Calculations:
To determine the service cost: Output of Unskilled help per day: 3.82 cubic metres
Unskilled help wages per day: ₦3,000.00
Total Unskilled help cost for 3.82 cubic metres: ₦3,000.00 / 3.82cubic metres = ₦785.34
For the Transportation cost: One Truck lorry transports 3.82 cubic metres per 5km radius, the transportation cost per lorry: ₦25,000.00
To dispose 10 cubic metres, calculate how many days the unskilled help will need: 10 cubic metres / 3.82 cubic metres per day = 2.61= 3 days
Transportation cost per cubic metres: ₦25,000.00 / 3.82 cubic metres = ₦6,544.50 per cubic metres
The total cost per cubic metre, including both labour and transportation, is ₦785.34 + ₦6,544.50 = ₦7,329.84 per cubic metres.
Schedule for Off-Site Disposal:
Assumed quantities to dispose: 10 cubic metres
Daily output per unskilled help: 3.82 cubic metres
Unskilled help wages per cubic metres: ₦785.34
Transportation cost per cubic metres: ₦6,544.50
Built up rate per cubic metres: ₦7,329.84
1.1.7 Pour Fillings (Laterite Sand Fillings)
Laterite sand fillings involve pouring and compacting layers of laterite sand. This material, rich in iron and aluminum oxides, provides excellent load-bearing capacity and drainage properties. The compacted fillings ensure uniform support beneath the foundation, minimizing settlement and structural issues. Proper compaction techniques, such as mechanical compaction or wetting and rolling, are employed to achieve the required density. Laterite sand fillings create a stable base for the foundation, contributing to the structural integrity and longevity of the building.
Assumptions:
The task is to determine the volume of lateritic sand needed to fill and make up the levels. For example, let's say you need to fill 25 cubic metres.
The material cost of 1 cubic metre of lateritic sand is ₦7,000.00. Adding 50% for shrinkage and waste amounts to ₦3,500.00, making the total ₦10,500.00 per cubic metres.
The rental of a compactor (tamper) costs ₦50,000.00.
The daily wage for the unskilled help is ₦2,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of lateritic sand is ₦10,500 per cubic metre, this includes the shrinkage and waste.
The compactor (tamper) costs ₦50,000.00 and can ramp up to 5 cubic metres per day. The equipment cost per cubic metre is ₦50,000.00 / 5 cubic metres = ₦10,000.00 per cubic metre.
One unskilled unskilled help can handle 2 cubic metres per day. The daily wage for the unskilled help is ₦2,400.00, the labour cost per cubic metre is ₦2,400.00 / 2 = ₦1,200.00 per cubic metre.
To pour 25 cubic metres, calculate how many days the unskilled help will need: 25 cubic metres / 2 cubic metres per day = 12.5 days or 13 days.
The total cost per cubic metre, including materials, equipment, and labour, is ₦10,500 (materials) + ₦10,000.00 (equipment) + ₦1,200.00 (labour) = ₦21,700.00 per cubic metre.
Schedule for Pouring Fillings (Laterite Sand Fillings):
Assumed quantities to fill: 25 cubic metres
Daily output per unskilled help: 2 cubic metres
Unskilled help wages per day: ₦2,400.00
Total cost per day for unskilled help: ₦2,400.00
Labour cost per cubic metre: ₦1,200.00
Material cost per cubic metre: ₦10,500.00
Equipment cost per cubic metre: ₦10,000.00
Built up rate per cubic metre: ₦21,700.00
1.1.8 Pour Fillings (Sharp Sand Fillings)
Pouring sharp sand fillings involves depositing and compacting sharp sand within the excavated area. This process aims to create a stable and level base for the foundation. Sharp sand, with its angular particles, facilitates good compaction and drainage properties, ensuring uniform support for the structure above. By eliminating voids and providing a solid substrate, sharp sand fillings enhance the load-bearing capacity of the foundation, contributing to the overall stability and durability of the building. Proper compaction techniques are employed to achieve the desired density and uniformity of the sand fillings.
Assumptions:
The task is to determine the volume of Sharp sand needed to fill and make up the levels. For example, let's say you need to fill 25 cubic metres.
The material cost of 1 cubic metre of Sharp sand is ₦6,500.00. Adding 30% for shrinkage and waste amounts to ₦1,950.00, making the total ₦8,450.00 per cubic metres.
The daily wage for the unskilled help is ₦3,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of lateritic is ₦8,450 per cubic metre, this includes the shrinkage and waste.
One unskilled help can handle 2 cubic metres per day. The daily wage for the help is ₦3,400.00, the labour cost per cubic metre is ₦3,400.00 / 2 cubic metres = ₦1,700.00 per cubic metre.
To pour 25 cubic metres, calculate how many days the unskilled help will need: 25 cubic metres / 2 cubic metres per day = 12.5 days.
The total cost per cubic metre, including materials and labour, is ₦8,450 (materials) + ₦1,700.00 (labour) = ₦11,150.00 per cubic metre.
Schedule for Pouring Fillings (Sharp Sand Fillings):
Assumed quantities to fill: 25 cubic metres
Daily output per unskilled help: 2 cubic metres
Unskilled help wages per day: ₦3,400.00
Total cost per day for unskilled help: ₦1,200.00
Labour cost per cubic metre: ₦1,700.00
Material cost per cubic metre: ₦8,450.00
Built up rate per cubic metre: ₦11,150.00
1.1.9 Pour Fillings (Hardcore Stone Fillings)
Hardcore stones filling, a crucial step in the foundation stage of building construction, involves filling and compacting layers of coarse aggregates like gravel or crushed stones. This process creates a stable and load-bearing base for the foundation. By evenly distributing the weight of the structure and providing adequate drainage, hardcore stones prevent settling or shifting over time, ensuring the structural integrity and longevity of the building. Proper compaction techniques are employed to achieve the desired density, maximizing the effectiveness of the hardcore stones in supporting the foundation and ultimately the entire building.
Assumptions:
The task is to determine the volume of Hardcore Stones needed to fill and make up the levels. For example, let's say you need to fill 10 cubic metres.
The material cost of 1 cubic metre of Hardcore Stones is ₦16,500.00. Adding 5% for waste amounts to ₦825.00, making the total ₦17,325.00 per cubic metres.
The daily wage for the unskilled help is ₦3,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of Hardcore Stones is ₦17,325.00 per cubic metre, this includes the 5% waste.
One unskilled help can handle 1 cubic metres per day. The daily wage for the help is ₦3,000.00, the labour cost per cubic metre is ₦3,000.00 / 1 = ₦3,000.00 per cubic metre.
To pour 10 cubic metres, calculate how many days the unskilled help will need: 10 cubic metres / 1 cubic metre per day = 10 days
The total cost per cubic metre, including materials and labour, is ₦17,325.00 (materials) + ₦3,000.00 (labour) = ₦20,325.00 per cubic metre.
Schedule for Pouring Fillings (Hardcore Stones):
Assumed quantities to fill: 10 cubic metres.
Daily output per unskilled help: 1 cubic metre
Unskilled help wages per day: ₦3,000.00
Total cost per day for unskilled help: ₦3,000.00
Labour cost per cubic metre: ₦3,000.00
Material cost per cubic metre: ₦17,325.00
Built up rate per cubic metre: ₦20,325.00
1.2 In-situ Concrete
In-situ concrete refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
1.2.1 Reinforcement Works
Reinforcement works in the foundation stage of building construction involve the arrangement and placing of steel bars (rebar) or mesh in preparation for concrete casting, to enhance its tensile strength. This process starts with designing the reinforcement layout according to structural requirements. Rebars are then cut, bent, and placed in formwork according to design specifications. These steel reinforcements are secured with ties or clips to maintain position during concrete pouring. Reinforcement in foundation concrete provides greater load-bearing capacity, prevents cracking under stress, and ensures the stability and longevity of the building by distributing loads more evenly across the structure.
1.2.1.1 Install Reinforcement in Column Bases
Steel rebar cages, prefabricated with vertical and horizontal bars, are lowered into the excavated column base. They're secured in place using spacers to maintain precise positioning within the concrete. These cages create a strong internal skeleton for the column bases, enabling them to transfer the building's weight properly to the soil.
Assumptions:
The task is to Install reinforcement steel bars in column bases and column starter. The materials used are reinforcement steel bars and binding wires. The standard length of reinforcement steel bars is 12 metres. The steel bars have the different diameters ranging from 32mm to 8mm. The standard size of binding wire is 20kg per roll.
Calculations:
For Different sizes of reinforcement steel bars:
A. 32mm Steel bar:
Weight per metre: 6.318 kg
Weight per 12m bar: 6.318 kg/m x 12m = 75.816 kg
Number of bars per tonne: 1 tonne / 75.816 kg ≈ 13 bars
B. 25mm Steel Bar:
Weight per metre: 3.856 kg
Weight per 12m bar: 3.856 kg/m x 12m = 46.272 kg
Number of bars per tonne: 1 tonne / 46.272 kg ≈ 22 bars
C. 20mm Steel bar:
Weight per metre: 2.468 kg
Weight per 12m bar: 2.468 kg/m x 12m = 29.616 kg
Number of bars per tonne: 1 tonne / 29.616 kg ≈ 34 bars
D. 16mm Steel bar:
Weight per metre: 1.58 kg
Weight per 12m bar: 1.58 kg/m x 12m = 18.96 kg
Number of bars per tonnes: 1 tonne / 18.96 kg ≈ 53 bars
E. 12mm Steel Bar:
Weight per metre: 0.888 kg
Weight per 12m bar: 0.888 kg/m x 12m = 10.656 kg
Number of bars per ton: 1 tonne / 10.656 kg ≈ 94 bars
F. 10mm Steel bar:
Weight per metre: 0.617 kg
Weight per 12m bar: 0.617 kg/m x 12m = 7.404 kg
Number of bars per ton: 1 tonne / 7.404 kg ≈ 135 bars
G. 8mm Steel bar:
Weight per metre: 0.395 kg
Weight per 12m bar: 0.395 kg/m x 12m = 4.74 kg
Number of bars per ton: 1 tonne / 4.74 kg ≈ 211 bars
2. Binding wire:
Weight per roll: 20 kg
Quantity required per ton of steel bars: 12 kg
Number of rolls required per tonne: 12 kg / 20 kg per roll = 0.6 rolls per tonne
Cost of binding wire per tonne of reinforcement bars: ₦42,000 x 0.6 = ₦25,200
Daily equipment rentals calculations:
Cutting machine: ₦50,000.00 per day
Angle grinder: ₦25,000.00 per day
Rebar bender (Electric): ₦150,000.00 per day
Total equipment Cost: ₦225,000.00per day
Average productivity: 1 tonne per day
Equipment cost per tonne: ₦225,000.00
Service:
Iron bender skilled: ₦10,000.00 per day
Iron bender semi-Skilled Placer: ₦7,500.00 per day
Iron bender semi-Skilled: ₦7,500.00 per day
Total service cost: ₦25,000.00 per day
Average productivity: 1 tonne per day
Service cost per tonne: ₦25,000.00
Total Installation cost per tonne:
This includes materials, equipment, and service costs. The exact cost depends on the size of the steel bars used. For example, if using 20mm steel bars:
Material Cost: Cost of steel bars ₦1,200,000.00 + (10% waste ₦120,000.00 )+ binding wire cost )
= (₦1,200,000.00 + 120,000.00 + ₦25,200.00)
= ₦1,345,200.00.
Total Cost per tonne = Material Cost + 225,000.00 (equipment) + 25,000.00 (service)
= ₦1,345,200.00 + ₦225,000.00 + ₦25,000.00
= ₦1,595,200.00 per tonne.
Schedule for Installing Reinforcement in Column Bases:
Assumed quantity: 1 tonne
Total material cost per tonne: ₦1,345,200.00
Equipment cost per tonne: ₦225,000.00
Service cost per tonne: ₦25,000.00
Total cost per tonne: ₦1,595,200.00 per tonne
1.2.1.2 Install Reinforcement in Column Starters
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 1.2.1.1
1.2.1.3 Install Reinforcement in Concrete Slabs
After concrete formwork has been set up around the slab area, reinforcement bars (rebar) are cut and bent to the required design, forming a mesh or grid pattern. These bars are securely tied together using binding wire, ensuring correct spacing and positioning. The rebar is supported on spacers to maintain the necessary concrete cover. Finally, concrete is poured over the reinforcement, fully encasing it, and allowed to cure, creating a solid foundation slab. This process aims to enhance strength and durability.
Refer to the calculations in 1.2.1.1
1.2.1.4 Install Reinforcement in Foundation Walls
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 1.2.1.1
1.2.1.5 Install Reinforcement in Ground Beams
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 1.2.1.1
1.2.1.6 Install Reinforcement in Plinth Beams
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 1.2.1.1
1.2.1.7 Install Reinforcement in Steel Rebar Reinforced Concrete Foundation Strip
Installing reinforcement in a steel rebar reinforced concrete foundation strip involves placing steel rebar bars in trenches or formwork, ensuring proper spacing and alignment as per design specifications. The rebar is typically bent or tied together using wire, forming a grid or cage structure. The reinforcement is then positioned in the foundation trench, ensuring it is securely supported before the concrete pour. This process strengthens the foundation, providing the necessary tensile strength to resist structural loads.
Refer to the calculations in 1.2.1.1
1.2.2 Install BRC Wire Mesh in Ground Floor Slab
After concrete formwork has been set up around the slab area, the BRC wire mesh, which reinforces the concrete, is cut to fit and placed on spacers to ensure it is positioned correctly within the slab. This is done to strengthen concrete structures, particularly in areas prone to cracking or stress. After installing the mesh, concrete is then poured over the mesh, ensuring it is evenly spread and vibrated to eliminate air pockets. Finally, the surface is smoothed, and the concrete is cured to gain strength.
Assumptions:
The tasks involves laying of BRC (British Reinforcement Concrete) wire mesh h in 1 square metre of ground floor slab.
The fabric mesh being used is the Type A142;
The BRC wire mesh sheet has dimensions of 15 metres by 2.1 metres, with a thickness of 3.5 millimetres, covering an area of 31.5 square metres.
The cost of this wire mesh is ₦12,000 per kilogram.
Calculations:
Materials required:
The BRC wire mesh sheet has dimensions of 15 metres by 2.1 metres, with a thickness of 3.5 millimetres, covering an area of 31.5 square metres. The cost of this wire mesh is ₦12,000.00 per kilogram. Since only a portion of the sheet is needed per square metre, this is calculated as 1/31.5 = 0.032 sheet per square metre. To account for overlap (referred to as "lapping"), we add a 20% allowance, resulting in a requirement of 0.0384 sheets per square metre. Therefore, the material cost per square metre is 0.0384 × ₦12,000.00 = ₦460.80.
Service:
Labour Cost (Cutting and Spreading) The process of cutting and spreading the BRC mesh requires one iron bender and one semi-skilled helper. Together, they can cover an area of 120 square metres per day. The daily wage for the iron bender is ₦3,500, and the semi-skilled helper earns ₦2,000 per day. Therefore, the labour cost per square metre is (₦3,500.00 + ₦2,000.00) / 120 = ₦46.00.
Daily equipment rentals calculations:
An angle grinder is used for cutting the wire mesh, with a rental cost of ₦15,000.00 per day. Since the team covers 120 square metres in a day, the equipment cost per square metre is ₦15,000.00 / 120 = ₦125.00.
Total Installation cost per square metre:
The total cost for installing 1 square metres of brc wire mesh includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦460.80 (Material costs), ₦46.00 (Service cost) and ₦125.00 (Equipment cost) which gives a total of ₦631.00.
Schedule for Installing BRC Wire Mesh in Ground Floor Slab:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦460.80
Service or labour cost per square metre: ₦46.00
Equipment cost per cost square metre: ₦125.00
Total cost of BRC wire mesh per square metre: ₦631.00
1.2.3 Concrete Works
In-situ concrete works refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
1.2.3.1 Pour Concrete into Blinding
Pouring concrete for blinding involves applying a thin layer of low-grade concrete over the prepared surface of the excavated area. This serves as a base to protect the underlying soil from contamination and to provide a level surface for subsequent construction activities. Blinding concrete also acts as a moisture barrier and helps in preventing the upward migration of groundwater. It ensures a stable foundation for the building structure and facilitates proper bonding with subsequent layers of concrete or the installation of foundation elements.
Assumptions:
The tasks involves pouring of concrete in 1 cubic metre of blinding to earth with the details below
Concrete mix ratio: Cement to Sand to Granite is 1:6:9.
Total portions: The mix consists of 16 parts.
Void in aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed.
Water cement ratio: The water-cement ratio is 0.5.
The output of the Workers is 2 cubic metres daily.
The daily rental cost of a concrete mixer is ₦120,000.00.
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg =2.77 bags ≈ 3 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 = 0.924 Tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 Tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625cubic metres x 0.5 = 0.048125 cubic metres. When converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres.
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250.00 per cubic metres.
Equipment Used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000.00 per cubic metres.
The total cost of materials per cubic metre:
Cement: 3 bags = 3 x 7,700 per bag = ₦23,100.00
Sand: 0.924 tonnes = 0.924 x 8,000 per tonne = ₦7,392.00
Granite: 1.472 tonnes = 1.472 x 13,000 per tonne = ₦19,136.00
Water: 48.125 litres (covered or measured under the preliminary items)
Total cost of materials = ₦49,628.00.
Total cost per cubic metre of concrete (Grade 10):
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦49,628.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦113,878.00.
Schedule for Pour Concrete into Blinding:
Assumed quantities: 1 cubic metre
Total material cost per cubic metre: ₦49,628.00
Service or labour cost per cubic metre: ₦4,250.00
Equipment cost per cubic metre: ₦60,000.00
Total cost of concrete in blinding: ₦113,878.00
1.2.3.2 Pour Concrete into Columns Bases
Pouring concrete in column bases during the foundation stage of building construction involves filling excavated areas with concrete to support vertical load-bearing columns. This process ensures a strong connection between the building's structure and its foundation, providing stability and load distribution. Once poured, the concrete is allowed to cure, forming a solid and durable foundation for the building's superstructure. This step is critical for ensuring the structural integrity and longevity of the entire construction project.
Assumptions:
Concrete Mix Composition:
The tasks involves pouring of concrete in 1 cubic metre of concrete in column base, column starter and concrete slab
Ratio: Cement to Sand to Granite is 1:2:4
Total Portions: The mix consists of 7 parts
Void in Aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste
Mix Volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed
Water Cement Ratio: The water-cement ratio is 0.5
The output of the Workers is 2 cubic metres daily
The daily rental cost of a concrete mixer is ₦120,000.00
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/7) = 0.22 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of cement will be 0.22 cubic metres x 1440 kg/m³ = 316.8 kg. The number of bags of cement is (50 kg each): 316.8 kg / 50 kg =2.77 bags ≈ 7 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (2/7) = 0.44 cubic metres. The density of Sand is 1600 kg/m³. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of sand will be 0.44 cubic metres x 1600 kg/m³ = 704 kg. The weight of Sand in tonnes is 704 kg / 1000 =0. 704 tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (4/7) = 0.88 cubic metres. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The density of granite is 1700 kg/m³. The mass of granite will be 0.88 cubic metres x 1700 kg/m³ = 1496 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.496 tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.22 cubic metres x 0.5 = 0.11 cubic metres. When converted to litres, 0.11 cubic metres x 1000 = 110 litres.
For the service required:
A skilled mason will charge ₦5,000 per day, while a semi-skilled mason is paid ₦3,500 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250 per cubic metre.
Equipment Used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000 per cubic metres
The total cost of materials per cubic metre:
Cement: 7 bags = 7 x 7,700 per bag =₦53,900.00
Sand: 0.704 tonnes = 0.704 x 8,000= ₦5,632.00
Granite: 1.496 tonnes= 1.496 x 13,000.00=₦19,448.00
Water: 110 litres (covered or measured under the preliminary items)
Total cost of materials =₦78,980.00
The total cost per cubic metre of concrete Grade 15:
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦78,980.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦143,230.00
Schedule for Pouring Concrete into Column Bases:
Total material cost per cubic metre: ₦78,980.00
Service or labour cost per cubic metre: ₦4,250
Equipment cost per cubic metre: ₦60,000
Total cost of concrete in blinding: ₦143,230.00
1.2.3.3 Pour Concrete into Column Starters
Pouring concrete in column starters during the foundation stage of building construction involves placing concrete into prepared formwork at the base of columns. This initial pour creates a sturdy foundation for the columns, ensuring proper load distribution and structural integrity. Column starters serve as the anchor points for vertical elements, transferring loads from the superstructure to the foundation. Careful attention is given to concrete quality, placement techniques, and curing processes to guarantee strength and durability. This essential step lays the groundwork for the vertical support system of the building, setting the stage for further construction above ground.
Refer to the calculations in 1.2.3.2
1.2.3.4 Pour Concrete into Footings
In the foundation stage of building construction, pouring concrete into footings is a critical step. Footings, typically made of reinforced concrete, distribute the building's weight evenly to the soil below. Concrete is poured into excavated trenches, forming the footings, which provide stability and support for the structure above. Proper placement and consolidation of concrete ensure structural integrity, while reinforcement bars enhance strength. The curing process is closely monitored to achieve the required strength and durability. Well-executed concrete footings are essential for the stability and longevity of the entire building.
Refer to the calculations in 1.2.3.2
1.2.3.5 Pour Concrete into Foundation Walls
Pouring concrete in the foundation wall during the foundation stage of building construction involves placing concrete into prepared formwork at the base of columns. This initial pour creates a sturdy foundation for the columns, ensuring proper load distribution and structural integrity. Foundation walls serve as the anchor points for vertical elements, transferring loads from the superstructure to the foundation. Careful attention is given to concrete quality, placement techniques, and curing processes to guarantee strength and durability. This essential step lays the groundwork for the vertical support system of the building, setting the stage for further construction above ground.
Refer to the calculations in 1.2.3.2
1.2.3.4 Pour Concrete into Ground Beams
Pouring concrete in ground beams during the foundation stage of building construction involves filling excavated areas with concrete to support vertical load-bearing columns. This process ensures a strong connection between the building's structure and its foundation, providing stability and load distribution. Once poured, the concrete is allowed to cure, forming a solid and durable foundation for the building's superstructure. This step is critical for ensuring the structural integrity and longevity of the entire construction project.
Refer to the calculations in 1.2.3.2
1.2.3.5 Pour Concrete into Plinth Beams
Pouring concrete into plinth beams is a critical step in substructure construction, forming the base framework for supporting the superstructure. The process involves mixing and placing fresh concrete into reinforced molds or forms within the plinth beams, ensuring proper compaction to eliminate air pockets. This solidifies the foundation, providing strength and stability. The reinforced concrete plinth beam transfers loads from the superstructure to the foundation soil, playing a crucial role in the overall structural integrity.
Refer to the calculations in 1.2.3.2
1.2.4. Formwork for In-situ Concrete
Formwork for in-situ concrete is a temporary mold into which concrete is poured and shaped during construction. It provides support until the concrete hardens and gains sufficient strength to support itself. Typically made from materials like timber, plywood, steel, or aluminum, formwork ensures accurate dimensions and surface finish of structural elements such as walls, columns, and slabs. It must be sturdy, leak-proof, and easy to remove once the concrete sets. Proper formwork design and installation are crucial for structural integrity, safety, and efficient construction progress, impacting the quality and durability of the final structure.
1.2.4.1 Fix Formwork to Columns Bases
During the foundation stage of building construction, installing formwork to the column base involves creating a temporary mold to shape and support the concrete until it hardens. The process begins with assembling formwork panels made of materials like timber, plywood, or steel around the column base area. These panels are secured tightly to prevent leakage and ensure the desired shape and dimensions. The formwork must be properly aligned and braced to withstand the pressure of the poured concrete. Once the concrete sets and gains sufficient strength, the formwork is carefully removed, leaving a solid and accurately shaped column base.
Assumptions:
The tasks involves fixing formwork to sides of column bases. The proposed area to be covered by formwork is 30 square metres.
The formwork to be used Marine board and Hardwood
Marine board size: 1.2 x 2.4 metres (2.88 m²), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used
Calculations:
Materials required:
A. Marine board: the area of the size is (2.88 m²), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00.
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00.
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 11 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00.
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 square metre = ₦5,520.00 per square metre
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metre
For the service required:
A skilled Carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000.00 per day. The labour output is 15 square metres per day, the cost per square metre is ₦9,000 / 15 m² = ₦600.00 per square metre
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 m². The equipment cost per square metre is ₦12,000 / 15 square metre = ₦800.00 per square metre
Total Cost:
The total cost for per square metre of fixing formwork to sides of concrete base, it includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00 per square metre and equipment cost ₦800.00/m²which gives ₦3,240.00 per square metre. The formwork to sides of concrete base is measured in linear metre with the average height to be 500mm. This gives the cost per linear metre to be ₦3,240.00 per square metre x 0.5m making ₦1,620.00 the cost per linear metre.
Schedule for Formwork in Column Bases:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
Built up rate per linear metre: ₦1,620.00 per metre
1.2.4.2 Fix Formwork to Sides of Columns Starters
In the foundation stage of building construction, installation of formwork to column starters involves setting up temporary molds around column footings. These molds, typically made from timber, steel, or aluminum, define the shape and size of the columns. They are securely positioned and aligned according to construction plans. Concrete is then poured into these formworks, allowing it to set and form the column bases. Proper installation ensures accurate dimensions and structural integrity, laying the foundation for the vertical elements of the building.
Assumptions:
The tasks involve fixing formwork to sides of column bases. The proposed area to be covered by formwork is 30 square metres
The formwork to be used Marine board and Hardwood:
Marine board size: 1.2 x 2.4 metres (2.88 square metres), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used
Calculations:
A. Marine board: the area of the size is (2.88 square metres), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00.
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00.
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 1 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00.
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 m² = ₦5,520.00 per square metres.
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metres.
For the service required:
A skilled Carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000 per day. The labour output is 15 square metres per day, per square metre is ₦9,000 / 15 square metres = ₦600.00/m².
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 per square metre . The equipment cost per cubic metre is ₦12,000.00 / 15 square metre = ₦800.00 per square metre
Total Cost:
The total cost for per square metre of fixing formwork to sides of concrete base, it includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00 per square metre and equipment cost ₦800.00 per square metre which gives ₦3,240.00 per square metre.
Schedule for Formwork in Column Starters:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
1.2.4.2 Fix Formwork to Foundation Walls
Fixing formwork to a foundation wall in building construction involves securely installing temporary molds to shape the concrete. The process begins by aligning the formwork to ensure the foundation wall’s dimensions and alignment match the design specifications. Stakes, braces, and clamps are used to stabilize the formwork, preventing movement during concrete pouring. Proper sealing ensures no leakage. Once the concrete cures, the formwork is carefully removed, leaving a smooth, accurate foundation surface for further construction.
Refer to the calculations in 1.2.4.1
1.2.4.3 Fix Formwork to Ground Beams
Fixing formwork to ground beams in substructure processes for building construction involves accurately positioning and securing wooden or metal panels to create molds for concrete. The process starts with measuring and aligning the formwork to match the beam layout, ensuring level surfaces and proper spacing. Formwork is fastened with stakes or clamps, providing stability. Reinforcement, like steel bars, is placed inside before pouring concrete. Proper fixing ensures structural integrity and accurate beam dimensions for fence support
Refer to the calculations in 1.2.4.1
1.2.4.4 Fix Formwork to Plinth Beams
Fixing formwork to plinth beams in building construction involves securely installing temporary molds to shape the concrete beams at the substructure level. The process includes aligning and bracing the formwork to maintain the desired dimensions and prevent leakage. Ensure a clean, stable surface and proper reinforcement placement before setting up the formwork. Adequate supports and ties are critical for stability during pouring. After concrete cures, carefully remove the formwork, ensuring minimal damage to the beam.
Refer to the calculations in 1.2.4.1
1.3. Masonry
Masonry involves the assembly of individual units like bricks, stones, or concrete blocks, bound together by mortar. It is used to build structures such as walls, foundations, and columns. Masonry offers durability, fire resistance, and aesthetic appeal, making it a popular choice for both structural and decorative purposes. The process requires skilled labor to ensure precise alignment and stability. Proper masonry construction provides excellent load-bearing capacity, thermal insulation, and soundproofing, contributing significantly to the overall integrity and functionality of a building.
1.3.1 Lay Hollow Filled Sandcrete Block Walls
Once the foundation trench has been prepped, leveled, and filled with concrete to create a footing, a crew lays a flat course of mortar. Sandcrete blocks are meticulously stacked on the mortar, then filled with concrete to increase its strength. Each block is checked for level and plumb, with a thin mortar layer spread before placing the next course. Staggering the block joints, row by row, builds a strong, interlocking foundation wall. This precise process continues until the entire foundation reaches its planned height.
Assumptions:
The tasks involve laying of hollow filled sandcrete blocks for 1 square metre of block wall.
Mortar mix ratio: Cement to Sand is 1:6, 1 part cement to 6 parts sand, the mix consists of 7 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5.
Size of block in consideration is 450mm x 225mm x 225mm blocks.
Calculations:
Materials for mortar composition:
A. Cement: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of cement will (1/7) x 1.20 cubic metres of wet concrete. This gives the volume of 0.17 cubic metres. Using the density 1440 kg/m³, the weight of cement will 0.17 cubic metres x 1,440 kg/m³ = 246.86 kg.
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg =4.93 bags ≈ 5 bags.
B. Sand: The cement to sand ratio 1:6 (1 part cement to 6 parts sand).The volume of sand required is (6/7) x 1.20 cubic metres = 1.03 cubic metres. The density of Sand is 1600 kg/m³. The weight of sand will be 1.03m³ x 1600 kg/m³ = 1645.71 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.645 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.17 cubic metres x 0.5 = 0.085 cubic metres. When converted to litres, 0.85 cubic metres x 1000 = 85.71 litres.
D. Blocks: The size of the block in consideration is 450mmx 225mm x 225mm blocks. The volume of mortar needed at one end of the one block is gotten by 0.450m x 0.225m x 0.225m = 0.02278125 cubic metres (V1).
The mortar is then added to the blocks with the dimensions 0.45 x 0.225 x 0.25 which give a volume of 0.02671875 cubic metres (V2). There is a void in the two sides in the block that is to be deducted is 2 x 0.15m x .15m x 0.025m=0.001125 cubic metres (D1). The volume of mortar per block is mortar volume per block is the difference between V2 and (V1+D1) = 0.02671875 cubic metres - (0.02671875 cubic metres + 0.001125 cubic metres) = 0.0028125 cubic metres per block. There are 10 blocks in a square metre of block wall and the volume of mortar per square metre for 225 blockworks is 0.028125 cubic metres per square metre.
For the materials in the mortar per square metre:
10 blocks of 225mm block wall are required per square metre.
The Cement for mortar, in 1 cubic metres of mortar, 4.937142857 bags of 50 kg each are required. For 0.028125 cubic metres per square metre, the amount of cement 0.028125 m³ x 4.937142857 =0.13948 bags per square metre.
The required Sand for mortar, in 1 cubic metre of mortar, 1.64571 tonnes of sand are required. For 0.028125 cubic metre per square metre, the amount of sand 0.028125 cubic metres x 1.64571 = 0.04631 tonnes.
The required water for mortar, for 1 cubic metres of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metres of mortar: Amount of water 0.028125 cubic metres x 85.71litres = 2.4098 litres.
For the plain concrete 1:6:9 poured in block wall.
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg = 2.77 bags ≈ 3 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 =0.924 Tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 Tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625 cubic metres x 0.5 = 0.048125 cubic metres, when converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres.
For the materials in the mortar per square metre:
The volume of the void concrete will fill per block is 0.001125m³. for 10 blocks of 225 x 450mm block wall are required 0.01125 cubic metres of concrete is required per square metre.
The Cement for concrete, in 1 cubic metres of concrete, 3 bags of 50 kg each are required. For 0.01125m³ per square metre, the amount of cement 0.01125 cubic metres x 3 bags =0.03375 bags per square metre.
The required Sand for concrete, in 1 cubic metres of concrete, 0.924 tonnes of sand are required. For 0.028125 cubic metre/square metre, the amount of sand 0.01125 cubic metres x 0. 924 = 0.010395 tonnes.
The required granite, in 1 cubic metre of concrete, 1.472 tonnes of Granite is required, the amount of granite 0.01125 cubic metre x 1.472 = 0.01656 tonnes.
The required water for concrete, for 1 cubic metre of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metre of mortar: Amount of water 0.028125 cubic metre x 85.71litres = 2.4098 litres.
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500.00 per day. The labour cost per cubic metre (assuming 5.5 square metre per day): ₦8,500.00 / 2.5 square metres = ₦3,400.00 per square metre.
Total cost of materials used per square metre:
Blocks- 10 blocks makes 1 square metre = 10 x 750= ₦7,500.00
Cement- 0.13948 + 0.03375 = 0.17323 bags x 7,700.00= ₦1,338.87
Sand- 0.04631 + 0.010395 = 0.056705 tonnes x 8,000.00 = ₦453.64
Granite- 0.01656 tonnes = 0.01656 tonnes x 13,000.00= ₦215.28
Total cost of materials = ₦9,294.66
Total cost:
The cost of laying a hollow filled sandcrete block wall per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦9,294.66 (Material costs) and ₦3,400.00 (Service cost) which gives a total of ₦12,694.66
Schedule for Hollow Filled Sandcrete Block Wall:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦9,294.66 per square metre
Service or labour cost per square metre: ₦3,400.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦12,694.66
1.3.2 Lay Sandcrete block wall
The foundation gets its base with a trench dug to the engineered depth. On this solid ground, a crew lays a flat course of mortar. Sandcrete blocks are meticulously stacked on the mortar, starting from corners. Each block is checked for level and plumb, with a thin mortar layer spread before placing the next course. Staggering the block joints, row by row, builds a strong, interlocking foundation wall. This precise process continues until the entire foundation reaches its planned height.
Assumptions:
The tasks involve laying of sandcrete block wall 1 square metre of block wall.
Mortar mix ratio: Cement to Sand is 1:6, 1 part cement to 6 parts sand, the mix consists of 7 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet Mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5.
Size of block in consideration is 450mmx 225mm x 225mm blocks.
Calculations:
Materials for mortar composition:
A. Cement: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of cement will (1/7) x 1.20 cubic metres of wet concrete. This gives the volume of 0.17 cubic metres. Using the density 1440 kg/m³, the weight of cement will 0.17 cubic metres x 1440 kg/m³ = 246.86 kg.
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg =4.93 bags ≈ 5 bags.
B. Sand: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of sand required is (6/7) x 1.20 cubic metres = 1.03 cubic metres. The density of Sand is 1600 kg/m³. The weight of sand will be 1.03 cubic metres x 1600 kg/m³ = 1645.71 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.645 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.17 cubic metres x 0.5 = 0.085 cubic metres. When converted to litres, 0.85 cubic metres x 1000 = 85.71 litres.
D. Blocks: The size of the block in consideration is 450mmx 225mm x 225mm blocks. The volume of mortar needed at one end of the one block is gotten by 0.450m x 0.225m x 0.225m = 0.02278125 cubic metres (V1). The Block is added to 25mm thick mortar which give 0.475m x 0.25 x 0.25 which gives a volume of 0.02268125 cubic metres (V1).
The mortar is then added to the blocks with the dimensions 0.45 x 0.225 x 0.25 which give a volume of 0.02671875 cubic metres (V2). There is a void in the two sides in the block that is to be deducted is 2 x 0.15m x .15m x 0.025m=0.001125m³ (D1). The volume of mortar per block is mortar volume per block is the difference between V2 and (V1+D1) = 0.02278125 cubic metres - (0.02671875 cubic metres + 0.001125 cubic metres) = 0.0028125 cubic metres per block. There are 10 blocks in a square metre of block wall and the volume of mortar per square metre for 225 Blockworks is 0.028125 cubic metres per square metre.
For the materials in the mortar per square metre:
10 blocks of 225mm block wall are required per square metre.
The Cement for mortar, In 1 cubic metres of mortar, 4.937142857 bags of 50 kg each are required. For 0.028125 cubic metres per square metre, the amount of cement 0.028125 cubic metres x 4.937142857 =0.13948 bags per square metre
The required Sand for mortar, In 1 m³ of mortar, 1.64571 tonnes of sand are required. For 0.028125 cubic metres per square metre, the amount of sand 0.028125 cubic metres x 1.64571 = 0.04631 tonnes
The required water for mortar, for 1 cubic metres of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metres of mortar: Amount of water 0.028125 cubic metres x 85.71litres = 2.4098 litres.
For the service required:
A skilled mason will charge ₦5,000 per day, while a semi-skilled mason is paid ₦3,500 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 5.5 square metre per day): ₦8,500 / 5.5 square metre = ₦1,545.45 per square metre.
Total cost of materials used per square metre:
Blocks- 10 blocks makes 1 square metre = 10 x 750= ₦7,500.00
Cement- 0.13948 bags x 7,700.00= ₦1,073.99
Sand- 0.04631 x tonnes x 8,000.00 = ₦370.48
Total cost of materials=₦8,944.47
Total cost:
The cost of laying an Sandcrete block wall per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦8,944.47 (Material costs) and ₦1,545.00 (Service cost) which gives a total of ₦10,489.92
Schedule for Hollow Filled Sandcrete Block Wall:
Assumed quantities: 1 square metre.
Total material cost per square metre: ₦9,294.66 per square metre.
Service or labour cost per square metre: ₦3,400.00 per square metre.
Equipment cost per square metre: ₦800.00 per square metre.
Built up rate per square metre: ₦12,694.66.
Entity - Barrier - Fence
Entity - Barrier - Fence
This refer to activities below the ground. The substructure of a building is everything that is constructed below ground level. It includes all the foundational work needed to support the building and keep it stable.
2.1 Excavation and Fillings
Excavation involves removing earth to create a foundation pit. This is done to reach the desired depth and shape necessary for the building's foundation. Fillings follow, adding and compacting material like soil or gravel into the excavated area to create a stable base. Both processes are essential for establishing a solid and secure foundation for the building.
2.1.1 Site Clearance - Vegetation
Site clearance in the foundation stage of building construction involves removing vegetation, debris, and existing structures to prepare the site for excavation. This includes demolishing old buildings, clearing trees and shrubs, and removing any underground utilities. Site clearance ensures a clean and safe area for construction activities to commence. Additionally, it allows for proper access and layout of the construction site according to architectural and engineering plans. Site clearance sets the stage for the foundation work to begin efficiently.
Assumptions:
The task is to clear a plot of land for construction, the total area of land that needs to be cleared in this scenario 200 square metres.
One unskilled help can clear 20 square metres per day. This involves removing vegetation on the land.
The daily wage for the unskilled help is ₦3,000.00.
Calculations:
The rate per square metre of the unskilled help is calculated as: ₦3,000.00 / 20 square metres = ₦150.00 square metres.
To clear 200 square metres, we need to calculate how many days the unskilled help will work: 200 square metres / 20 square metres per day = 10 days.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily wage: 10 days x ₦3,000.00 per day = ₦30,000.00.
Schedule of Site Clearance:
Assumed quantities: 200 square metres
Daily output per unskilled help: 20 square metres
Number of days required: 10 days
Daily wage per unskilled help: ₦3,000.00
Total cost for service or labour: ₦30,000.00
Built up rate for labour: ₦150.00 per square metres
2.1.2 Topsoil Excavation
Topsoil excavation in the foundation stage of building construction involves removing the uppermost soil layer, which is rich in organic material and unsuitable for supporting structural loads. This process ensures a stable base for the foundation by eliminating potential settlement and instability caused by the organic content. Excavation typically reaches a depth where the soil is more compact and capable of bearing the structure's weight. The removed topsoil can be stored and reused for landscaping purposes. Properly executed topsoil excavation is critical for establishing a solid, reliable foundation and preventing future structural issues.
Assumptions:
The task is to determine the volume of earth that needs to be excavated, we have to excavate a depth of 0.175 metres of a 200 square metres area of land. The result will get you 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the Unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help is ₦2,200.00
Calculations:
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days.
The unit rate is the total cost divided by the service output. That is ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00.
Schedule of Topsoil Excavation:
Assumed Quantities: 35 cubic metres
Daily output per unskilled help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
2.1.3 Trench Excavation
Trench excavation involves digging narrow, elongated depressions in the ground to prepare for foundation footings, utility lines, and drainage systems. This process requires precise measurements and careful planning to ensure proper depth, width, and alignment. Excavated soil is typically stored nearby for backfilling. Safety measures, like trench shoring or shielding, are essential to prevent collapses and protect workers. Once the trench is prepared, it serves as a stable base for laying the building's foundation elements, ensuring structural integrity and proper support for the overall construction.
Assumptions:
The task is to determine the volume of earth soil in the trench that needs to be excavated. For example, let's say you need to excavate a trench of with a total volume of 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help, including tools, is ₦2,200.00.
Calculations:
Each day, the unskilled help will have an output of work 3.5 cubic metres of earth.
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00.
Schedule of Trench Excavation:
Assumed quantities to excavate: 35 cubic metres
Daily output per unskilled Help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
2.1.4 Pour Backfill to Trench Excavation
In the foundation stage of building construction, pouring backfill into trench excavations involves refilling and compacting the void left after excavation with suitable materials like soil or gravel. This serves to provide support to the foundation, enhancing its stability and preventing settlement. Backfilling also helps in improving drainage around the foundation and protects against soil erosion. Proper compaction of the backfill material is essential to ensure uniform support and minimize future settlement.
Assumptions:
The task is to determine the volume of earth that needs to be backfilled to the sides of excavation. For example, let's say you need to backfill 40 cubic metres.
Calculations:
One unskilled help can backfill 4 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00.
Therefore, the total cost per day for the unskilled help is ₦2,200.
To backfill 40 cubic metres, calculate how many days the unskilled help will need: 40 cubic metres / 4 cubic metres per day = 10 days.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.
Cost per cubic metre is ₦22,000/40 cubic metres = ₦550 per cubic metres.
Schedule for Pouring Backfill to Trench Excavation:
Assumed quantities to backfill: 40 cubic metres
Daily output per unskilled help: 4 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost per day: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦550 per cubic metre
2.1.5 Disposal (On-Site)
On-site disposal in building construction involves managing and disposing of excavated soil, debris, or waste materials within the construction site itself. This process requires designated areas for temporary storage, sorting, and proper disposal methods, such as recycling or landfilling. On-site disposal helps minimize transportation costs and environmental impact by reducing the need for off-site hauling. Effective on-site disposal practices contribute to efficient project management and sustainable construction practices, ensuring responsible waste management throughout the building process.
Assumptions:
The task is to determine the volume of excavated materials that needs to be disposed to a spoil heap 1 metre away, assuming the volume of excavated material is 20 cubic metres.
Disposal volume: Workers can handle 4 cubic metres of disposal per day.
Service Cost: It costs ₦2,200.00 for the unskilled help each day.
Calculations:
One unskilled help can backfill 4 cubic metres per day.
Unit rate: To find the unit rate per cubic metre, divide the total cost by the labour output: ₦2,200 / 4 cubic metres = ₦550 per cubic metres.
To dispose of 20 cubic metres, calculate how many days the unskilled unskilled help will need: 20 cubic metres / 4 cubic metres per day = 5 days.
The total cost for labour and tools over the entire period is calculated by multiplying the number of days by the daily cost: 5 days x ₦2,200 per day = ₦11,000.00.
Schedule for On-Site Disposal:
Assumed quantities to dispose: 20 cubic metres
Daily output per unskilled help: 4 cubic metres
Unskilled help wages per Day: ₦2,200.00
Total cost for service or labour: ₦11,000.00
Built up rate: ₦550 per cubic metre
2.1.6 Task Disposal (Off-Site)
Off-site disposal is an aspect of the construction process where excavated soil, debris, or waste materials generated during site preparation, excavation, or demolition are transported and disposed of at designated facilities away from the construction site. This involves loading the materials onto trucks or containers and transporting them to licensed disposal sites or recycling facilities. Off-site disposal ensures proper waste management, environmental protection, and compliance with regulations. It also helps maintain a clean and safe construction site, minimizing environmental impact and ensuring the efficient progress of the construction project.
Assumptions:
The task is to determine the volume of excavated materials that need to be disposed of. For example, let's say you need to dispose of 10 cubic metres of excavated earth.
One Unskilled help can load the disposal of 3.82 cubic metres per day averagely.
A 5 tonne Truck can transport 3.82 cubic metres of excavated materials per trip within a 5km radius. The transportation cost per lorry is ₦25,000.00.
Calculations:
To determine the service cost: Output of Unskilled help per day: 3.82 cubic metres.
Unskilled help wages per day: ₦3,000.00.
Total Unskilled help cost for 3.82 cubic metres: ₦3,000.00 / 3.82 cubic metres = ₦785.34.
For the Transportation cost: One Truck lorry transports 3.82 cubic metres per 5km radius, the transportation cost per lorry: ₦25,000.00.
To dispose 10 cubic metres, calculate how many days the unskilled help will need: 10 cubic metres / 3.82 cubic metres per day = 2.61 = 3 days
Transportation cost per cubic metres: ₦25,000.00 / 3.82 cubic metres = ₦6,544.50 per cubic metres.
The total cost per cubic metre, including both labour and transportation, is ₦785.34 + ₦6,544.50 = ₦7,329.84 per cubic metres.
Schedule for Off-Site Disposal:
Assumed quantities to dispose: 10 cubic metres
Daily output per unskilled help: 3.82 cubic metres
Unskilled help wages per cubic metres: ₦785.34
Transportation cost per cubic metres: ₦6,544.50
Built up rate per cubic metres: ₦7,329.84
2.2 In-Situ Concrete
In-situ concrete refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
2.2.1 Reinforcement Works
Reinforcement works in the foundation stage of building construction involve the arrangement and placing of steel bars (rebar) or mesh in preparation for concrete casting, to enhance its tensile strength. This process starts with designing the reinforcement layout according to structural requirements. Rebars are then cut, bent, and placed in formwork according to design specifications. These steel reinforcements are secured with ties or clips to maintain position during concrete pouring. Reinforcement in foundation concrete provides greater load-bearing capacity, prevents cracking under stress, and ensures the stability and longevity of the building by distributing loads more evenly across the structure.
2.2.1.1 Install Reinforcement in Column Bases
Steel rebar cages, prefabricated with vertical and horizontal bars, are lowered into the excavated column base. They're secured in place using spacers to maintain precise positioning within the concrete. These cages create a strong internal skeleton for the column bases, enabling them to transfer the building's weight properly to the soil.
Assumptions:
The task is to Install reinforcement steel bars in column bases and column starter. The materials used are reinforcement steel bars and binding wires. The standard length of reinforcement steel bars is 12 metres. The steel bars have the different diameters ranging from 32mm to 8mm. The standard size of binding wire is 20kg per roll.
Calculations:
For Different sizes of reinforcement steel bars:
A. 32mm Steel bar:
Weight per metre: 6.318 kg
Weight per 12m bar: 6.318 kg/m x 12m = 75.816 kg
Number of bars per tonne: 1 tonne / 75.816 kg ≈ 13 bars
B. 25mm Steel Bar:
Weight per metre: 3.856 kg
Weight per 12m bar: 3.856 kg/m x 12m = 46.272 kg
Number of bars per tonne: 1 tonne / 46.272 kg ≈ 22 bars
C. 20mm Steel bar:
Weight per metre: 2.468 kg
Weight per 12m bar: 2.468 kg/m x 12m = 29.616 kg
Number of bars per tonne: 1 tonne / 29.616 kg ≈ 34 bars
D. 16mm Steel bar:
Weight per metre: 1.58 kg
Weight per 12m bar: 1.58 kg/m x 12m = 18.96 kg
Number of bars per tonnes: 1 tonne / 18.96 kg ≈ 53 bars
E. 12mm Steel Bar:
Weight per metre: 0.888 kg
Weight per 12m bar: 0.888 kg/m x 12m = 10.656 kg
Number of bars per ton: 1 tonne / 10.656 kg ≈ 94 bars
F. 10mm Steel bar:
Weight per metre: 0.617 kg
Weight per 12m bar: 0.617 kg/m x 12m = 7.404 kg
Number of bars per ton: 1 tonne / 7.404 kg ≈ 135 bars
G. 8mm Steel bar:
Weight per metre: 0.395 kg
Weight per 12m bar: 0.395 kg/m x 12m = 4.74 kg
Number of bars per ton: 1 tonne / 4.74 kg ≈ 211 bars
2. Binding wire:
Weight per roll: 20 kg
Quantity required per ton of steel bars: 12 kg
Number of rolls required per tonne: 12 kg / 20 kg per roll = 0.6 rolls per tonne
Cost of binding wire per tonne of reinforcement bars: ₦42,000 x 0.6 = ₦25,200
Daily equipment rentals calculations:
Cutting machine: ₦50,000.00 per day
Angle grinder: ₦25,000.00 per day
Rebar bender (Electric): ₦150,000.00 per day
Total equipment Cost: ₦225,000.00per day
Average productivity: 1 tonne per day
Equipment cost per tonne: ₦225,000.00
Service:
Iron bender skilled: ₦10,000.00 per day
Iron bender semi-Skilled Placer: ₦7,500.00 per day
Iron bender semi-Skilled: ₦7,500.00 per day
Total service cost: ₦25,000.00 per day
Average productivity: 1 tonne per day
Service cost per tonne: ₦25,000.00
Total Installation cost per tonne:
This includes materials, equipment, and service costs. The exact cost depends on the size of the steel bars used. For example, if using 20mm steel bars:
Material Cost: Cost of steel bars ₦1,200,000.00 + (10% waste ₦120,000.00 )+ binding wire cost )
= (₦1,200,000.00 + 120,000.00 + ₦25,200.00)
= ₦1,345,200.00
Total Cost per tonne = Material Cost + 225,000.00 (equipment) + 25,000.00 (service)
= ₦1,345,200.00 + ₦225,000.00 + ₦25,000.00
= ₦1,595,200.00 per tonne
Schedule for Installing Reinforcement in Column Bases:
Assumed quantity: 1 tonne
Total material cost per tonne: ₦1,345,200.00
Equipment cost per tonne: ₦225,000.00
Service cost per tonne: ₦25,000.00
Total cost per tonne: ₦1,595,200.00 per tonne
2.2.1.2 Install Reinforcement in Column Starters
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 2.2.1.1
2.2.1.3 Install Reinforcement in Foundation Walls
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 2.2.1.1
2.2.1.4 Install Reinforcement in Ground Beams
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 2.2.1.1
2.2.1.5 Install Reinforcement in Plinth Beams
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 2.2.1.1
2.2.3 Concrete Works
In-situ concrete works refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
2.2.3.1 Pour Concrete into Blinding
Pouring concrete for blinding involves applying a thin layer of low-grade concrete over the prepared surface of the excavated area. This serves as a base to protect the underlying soil from contamination and to provide a level surface for subsequent construction activities. Blinding concrete also acts as a moisture barrier and helps in preventing the upward migration of groundwater. It ensures a stable foundation for the building structure and facilitates proper bonding with subsequent layers of concrete or the installation of foundation elements.
Assumptions:
The tasks involves pouring of concrete in 1 cubic metre of blinding to earth with the details below
Concrete mix ratio: Cement to Sand to Granite is 1:6:9.
Total portions: The mix consists of 16 parts.
Void in aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed.
Water cement ratio: The water-cement ratio is 0.5.
The output of the Workers is 2 cubic metres daily.
The daily rental cost of a concrete mixer is ₦120,000.00.
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg =2.77 bags ≈ 3 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 = 0.924 Tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 Tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625cubic metres x 0.5 = 0.048125 cubic metres. When converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres.
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250.00 per cubic metres.
Equipment Used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000.00 per cubic metres.
The total cost of materials per cubic metre:
Cement: 3 bags = 3 x 7,700 per bag = ₦23,100.00
Sand: 0.924 tonnes = 0.924 x 8,000 per tonne = ₦7,392.00
Granite: 1.472 tonnes = 1.472 x 13,000 per tonne = ₦19,136.00
Water: 48.125 litres (covered or measured under the preliminary items)
Total cost of materials = ₦49,628.00
Total cost per cubic metre of concrete (Grade 10):
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦49,628.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦113,878.00
Schedule for Pouring Concrete into Blinding:
Assumed quantities: 1 cubic metre
Total material cost per cubic metre: ₦49,628.00
Service or labour cost per cubic metre: ₦4,250.00
Equipment cost per cubic metre: ₦60,000.00
Total cost of concrete in blinding: ₦113,878.00
2.2.3.2 Pour Concrete into Column Bases
Pouring concrete in column bases during the foundation stage of building construction involves filling excavated areas with concrete to support vertical load-bearing columns. This process ensures a strong connection between the building's structure and its foundation, providing stability and load distribution. Once poured, the concrete is allowed to cure, forming a solid and durable foundation for the building's superstructure. This step is critical for ensuring the structural integrity and longevity of the entire construction project.
Assumptions:
Concrete Mix Composition:
The task involves pouring of concrete in 1 cubic metre of concrete in column base, column starter and concrete slab.
Ratio: Cement to Sand to Granite is 1:2:4.
Total Portions: The mix consists of 7 parts.
Void in Aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste.
Mix Volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed.
Water Cement Ratio: The water-cement ratio is 0.5.
The output of the Workers is 2 cubic metres daily.
The daily rental cost of a concrete mixer is ₦120,000.00.
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/7) = 0.22 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of cement will be 0.22 cubic metres x 1440 kg/m³ = 316.8 kg. The number of bags of cement is (50 kg each): 316.8 kg / 50 kg =2.77 bags ≈ 7 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (2/7) = 0.44 cubic metres. The density of Sand is 1600 kg/m³. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of sand will be 0.44 cubic metres x 1600 kg/m³ = 704 kg. The weight of Sand in tonnes is 704 kg / 1000 =0. 704 Tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (4/7) = 0.88 cubic metres. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The density of granite is 1700 kg/m³. The mass of granite will be 0.88 cubic metres x 1700 kg/m³ = 1496 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.496 Tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.22 cubic metres x 0.5 = 0.11 cubic metres. When converted to litres, 0.11 cubic metres x 1000 = 110 litres.
For the service required:
A skilled mason will charge ₦5,000 per day, while a semi-skilled mason is paid ₦3,500 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250 per cubic metre.
Equipment Used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000 per cubic metres.
The total cost of materials per cubic metre:
Cement: 7 bags = 7 x 7,700 per bag =₦53,900.00
Sand: 0.704 tonnes = 0.704 x 8,000= ₦5,632.00
Granite: 1.496 tonnes= 1.496 x 13,000.00=₦19,448.00
Water: 110 litres (covered or measured under the preliminary items)
Total cost of materials =₦78,980.00
The total cost per cubic metre of concrete Grade 15:
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦78,980.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦143,230.00
Schedule for Pouring Concrete into Column Bases:
Total material cost per cubic metre: ₦78,980.00
Service or labour cost per cubic metre: ₦4,250
Equipment cost per cubic metre: ₦60,000
Total cost of concrete in blinding: ₦143,230.00
2.2.3.3 Pour Concrete into Columns Starters
Pouring concrete in column starters during the foundation stage of building construction involves placing concrete into prepared formwork at the base of columns. This initial pour creates a sturdy foundation for the columns, ensuring proper load distribution and structural integrity. Column starters serve as the anchor points for vertical elements, transferring loads from the superstructure to the foundation. Careful attention is given to concrete quality, placement techniques, and curing processes to guarantee strength and durability. This essential step lays the groundwork for the vertical support system of the building, setting the stage for further construction above ground.
Refer to the calculations in 2.2.3.2
2.2.3.4 Pour Concrete into Footings
In the foundation stage of building construction, pouring concrete into footings is a critical step. Footings, typically made of reinforced concrete, distribute the building's weight evenly to the soil below. Concrete is poured into excavated trenches, forming the footings, which provide stability and support for the structure above. Proper placement and consolidation of concrete ensure structural integrity, while reinforcement bars enhance strength. The curing process is closely monitored to achieve the required strength and durability. Well-executed concrete footings are essential for the stability and longevity of the entire building.
Refer to the calculations in 2.2.3.2
2.2.3.5 Pour Concrete into Foundation Walls
Pouring concrete in the foundation wall during the foundation stage of building construction involves placing concrete into prepared formwork at the base of columns. This initial pour creates a sturdy foundation for the columns, ensuring proper load distribution and structural integrity. Foundation walls serve as the anchor points for vertical elements, transferring loads from the superstructure to the foundation. Careful attention is given to concrete quality, placement techniques, and curing processes to guarantee strength and durability. This essential step lays the groundwork for the vertical support system of the building, setting the stage for further construction above ground.
Refer to the calculations in 2.2.3.2
2.2.3.4 Pour Concrete into Ground Beams
Pouring concrete in ground beams during the foundation stage of building construction involves filling excavated areas with concrete to support vertical load-bearing columns. This process ensures a strong connection between the building's structure and its foundation, providing stability and load distribution. Once poured, the concrete is allowed to cure, forming a solid and durable foundation for the building's superstructure. This step is critical for ensuring the structural integrity and longevity of the entire construction project.
Refer to the calculations in 1.2.3.2
2.2.3.5 Pour Concrete into Plinth Beams
Pouring concrete into plinth beams is a critical step in substructure construction, forming the base framework for supporting the superstructure. The process involves mixing and placing fresh concrete into reinforced molds or forms within the plinth beams, ensuring proper compaction to eliminate air pockets. This solidifies the foundation, providing strength and stability. The reinforced concrete plinth beam transfers loads from the superstructure to the foundation soil, playing a crucial role in the overall structural integrity.
Refer to the calculations in 2.2.3.2
2.2.4. Formwork for In-Situ Concrete
Formwork for in-situ concrete is a temporary mold into which concrete is poured and shaped during construction. It provides support until the concrete hardens and gains sufficient strength to support itself. Typically made from materials like timber, plywood, steel, or aluminum, formwork ensures accurate dimensions and surface finish of structural elements such as walls, columns, and slabs. It must be sturdy, leak-proof, and easy to remove once the concrete sets. Proper formwork design and installation are crucial for structural integrity, safety, and efficient construction progress, impacting the quality and durability of the final structure.
2.2.4.1 Fix Formwork to Column Bases
During the foundation stage of building construction, installing formwork to the column base involves creating a temporary mold to shape and support the concrete until it hardens. The process begins with assembling formwork panels made of materials like timber, plywood, or steel around the column base area. These panels are secured tightly to prevent leakage and ensure the desired shape and dimensions. The formwork must be properly aligned and braced to withstand the pressure of the poured concrete. Once the concrete sets and gains sufficient strength, the formwork is carefully removed, leaving a solid and accurately shaped column base.
Assumptions:
The tasks involves fixing formwork to sides of column bases. The proposed area to be covered by formwork is 30 square metres.
The formwork to be used Marine board and Hardwood
Marine board size: 1.2 x 2.4 metres (2.88 m²), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used.
Calculations:
Materials required:
A. Marine board: the area of the size is (2.88 m²), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00.
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00.
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 11 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00.
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 square metre = ₦5,520.00 per square metre
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metre
For the service required:
A skilled Carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000.00 per day. The labour output is 15 square metres per day, the cost per square metre is ₦9,000 / 15 m² = ₦600.00 per square metre.
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 m². The equipment cost per square metre is ₦12,000 / 15 square metre = ₦800.00 per square metre.
Total Cost:
The total cost for per square metre of fixing formwork to sides of concrete base, it includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00 per square metre and equipment cost ₦800.00/m²which gives ₦3,240.00 per square metre. The formwork to sides of concrete base are measured in linear metre with the average height to be 500mm. This gives the cost per linear metre to be ₦3,240.00 per square metre x 0.5m making ₦1,620.00 the cost per linear metre.
Schedule for Fixing Formwork in Column Bases:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
Built up rate per linear metre: ₦1,620.00 per metre
2.2.4.2 Fix Formwork to Sides of Columns Starters
In the foundation stage of building construction, installation of formwork to column starters involves setting up temporary molds around column footings. These molds, typically made from timber, steel, or aluminum, define the shape and size of the columns. They are securely positioned and aligned according to construction plans. Concrete is then poured into these formworks, allowing it to set and form the column bases. Proper installation ensures accurate dimensions and structural integrity, laying the foundation for the vertical elements of the building.
Assumptions:
The tasks involves fixing formwork to sides of column bases. The proposed area to be covered by formwork is 30 square metres
The formwork to be used Marine board and Hardwood:
Marine board size: 1.2 x 2.4 metres (2.88 square metres), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used.
Calculations:
A. Marine board: the area of the size is (2.88 square metres), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 1 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 m² = ₦5,520.00 per square metres
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metres.
For the service required:
A skilled Carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000 per day. The labour output is 15 square metres per day, per square metre is ₦9,000 / 15 square metres = ₦600.00/m²
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 per square metre . The equipment cost per cubic metre is ₦12,000.00 / 15 square metre = ₦800.00 per square metre
Total Cost:
The total cost for per square metre of fixing formwork to sides of concrete base, it includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00/m² and equipment cost ₦800.00 per square metre which gives ₦3,240.00 per square metre.
Schedule for Formwork to Sides of Columns Starters:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
2.2.4.2 Fix Formwork to Foundation Walls
Fixing formwork to a foundation wall in building construction involves securely installing temporary molds to shape the concrete. The process begins by aligning the formwork to ensure the foundation wall’s dimensions and alignment match the design specifications. Stakes, braces, and clamps are used to stabilize the formwork, preventing movement during concrete pouring. Proper sealing ensures no leakage. Once the concrete cures, the formwork is carefully removed, leaving a smooth, accurate foundation surface for further construction.
Refer to the calculations in 2.2.4.1
2.2.4.3 Fix Formwork to Ground Beams
Fixing formwork to ground beams in substructure processes for building construction involves accurately positioning and securing wooden or metal panels to create molds for concrete. The process starts with measuring and aligning the formwork to match the beam layout, ensuring level surfaces and proper spacing. Formwork is fastened with stakes or clamps, providing stability. Reinforcement, like steel bars, is placed inside before pouring concrete. Proper fixing ensures structural integrity and accurate beam dimensions for fence support
Refer to the calculations in 2.2.4.1
2.2.4.4 Fix Formwork to Plinth Beams
Fixing formwork to plinth beams in building construction involves securely installing temporary molds to shape the concrete beams at the substructure level. The process includes aligning and bracing the formwork to maintain the desired dimensions and prevent leakage. Ensure a clean, stable surface and proper reinforcement placement before setting up the formwork. Adequate supports and ties are critical for stability during pouring. After concrete cures, carefully remove the formwork, ensuring minimal damage to the beam.
Refer to the calculations in 2.2.4.1
2.3. Masonry
Masonry involves the assembly of individual units like bricks, stones, or concrete blocks, bound together by mortar. It is used to build structures such as walls, foundations, and columns. Masonry offers durability, fire resistance, and aesthetic appeal, making it a popular choice for both structural and decorative purposes. The process requires skilled labor to ensure precise alignment and stability. Proper masonry construction provides excellent load-bearing capacity, thermal insulation, and soundproofing, contributing significantly to the overall integrity and functionality of a building.
2.3.1 Lay Hollow Filled Sandcrete Block Wall
Once the foundation trench has been prepped, leveled, and filled with concrete to create a footing, a crew lays a flat course of mortar. Sandcrete blocks are meticulously stacked on the mortar, then filled with concrete to increase its strength. Each block is checked for level and plumb, with a thin mortar layer spread before placing the next course. Staggering the block joints, row by row, builds a strong, interlocking foundation wall. This precise process continues until the entire foundation reaches its planned height.
Assumptions:
The tasks involve laying of hollow filled sandcrete blocks for 1 square metre of block wall.
Mortar mix ratio: Cement to Sand is 1:6, 1 part cement to 6 parts sand, the mix consists of 7 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet Mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5.
Size of block in consideration is 450mmx 225mm x 225mm blocks
Calculations:
Materials for mortar composition:
A. Cement: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of cement will (1/7) x 1.20 cubic metres of wet concrete. This gives the volume of 0.17 cubic metres. Using the density 1440 kg/m³, the weight of cement will 0.17 cubic metres x 1,440 kg/m³ = 246.86 kg.
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg =4.93 bags ≈ 5 bags.
B. Sand: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of sand required is (6/7) x 1.20 cubic metres = 1.03 cubic metres. The density of Sand is 1600 kg/m³. The weight of sand will be 1.03m³ x 1600 kg/m³ = 1645.71 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.645 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.17 cubic metres x 0.5 = 0.085 cubic metres. When converted to litres, 0.85 cubic metres x 1000 = 85.71 litres.
D. Blocks: The size of the block in consideration is 450mmx 225mm x 225mm blocks. The volume of mortar needed at one end of the one block is gotten by 0.450m x 0.225m x 0.225m = 0.02278125 cubic metres (V1).
The mortar is then added to the blocks with the dimensions 0.45 x 0.225 x 0.25 which give a volume of 0.02671875 cubic metres (V2). There is a void in the two sides in the block that is to be deducted is 2 x 0.15m x .15m x 0.025m=0.001125 cubic metres (D1). The volume of mortar per block is mortar volume per block is the difference between V2 and (V1+D1) = 0.02671875 cubic metres - (0.02671875 cubic metres + 0.001125 cubic metres) = 0.0028125 cubic metres per block. There are 10 blocks in a square metre of block wall and the volume of mortar per square metre for 225 blockworks is 0.028125 cubic metres per square metre.
For the materials in the mortar per square metre:
10 blocks of 225mm block wall are required per square metre.
The Cement for mortar, In 1 cubic metres of mortar, 4.937142857 bags of 50 kg each are required. For 0.028125 cubic metres per square metre, the amount of cement 0.028125 m³ x 4.937142857 =0.13948 bags per square metre.
The required Sand for mortar, in 1 cubic metre of mortar, 1.64571 tonnes of sand are required. For 0.028125 cubic metre per square metre, the amount of sand 0.028125 cubic metres x 1.64571 = 0.04631 tonnes.
The required water for mortar, for 1 cubic metres of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metres of mortar: Amount of water 0.028125 cubic metres x 85.71litres = 2.4098 litres.
For the plain concrete 1:6:9 poured in block wall:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg = 2.77 bags ≈ 3 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 =0. 924 Tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 Tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625 cubic metres x 0.5 = 0.048125 cubic metres, when converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres.
For the materials in the mortar per square metre:
The volume of the void concrete will fill per block is 0.001125m³. for 10 blocks of 225 x 450mm block wall are required 0.01125 cubic metres of concrete is required per square metre.
The Cement for concrete, in 1 cubic metres of concrete, 3 bags of 50 kg each are required. For 0.01125m³ per square metre, the amount of cement 0.01125 cubic metres x 3 bags =0.03375 bags per square metre.
The required Sand for concrete, in 1 cubic metres of concrete, 0.924 tonnes of sand are required. For 0.028125 cubic metre/square metre, the amount of sand 0.01125 cubic metres x 0. 924 = 0.010395 tonnes.
The required granite , in 1 cubic metre of concrete, 1.472 tonnes of Granite is required, the amount of granite 0.01125 cubic metre x 1.472 = 0.01656 tonnes
The required water for concrete, for 1 cubic metre of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metre of mortar: Amount of water 0.028125 cubic metre x 85.71 litres = 2.4098 litres.
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500.00 per day. The labour cost per cubic metre (assuming 5.5 square metre per day): ₦8,500.00 / 2.5 square metres = ₦3,400.00 per square metre.
Total cost of materials used per square metre:
Blocks- 10 blocks make 1 square metre = 10 x 750= ₦7,500.00
Cement- 0.13948 + 0.03375 = 0.17323 bags x 7,700.00= ₦1,338.87
Sand- 0.04631 + 0.010395 = 0.056705 tonnes x 8,000.00 = ₦453.64
Granite- 0.01656 tonnes = 0.01656 tonnes x 13,000.00= ₦215.28
Total cost of materials = ₦9,294.66
Total cost:
The cost of laying a hollow filled sandcrete block wall per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦9,294.66 (Material costs) and ₦3,400.00 (Service cost) which gives a total of ₦12,694.66
Schedule for Hollow Filled Sandcrete Block Wall:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦9,294.66 per square metre
Service or labour cost per square metre: ₦3,400.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦12,694.66
2.3.2 Lay Sandcrete Block Wall
The foundation gets its base with a trench dug to the engineered depth. On this solid ground, a crew lays a flat course of mortar. Sandcrete blocks are meticulously stacked on the mortar, starting from corners. Each block is checked for level and plumb, with a thin mortar layer spread before placing the next course. Staggering the block joints, row by row, builds a strong, interlocking foundation wall. This precise process continues until the entire foundation reaches its planned height.
Assumptions:
The tasks involve laying of sandcrete blocks for 1 square metre of block wall.
Mortar mix ratio: Cement to Sand is 1:6, 1 part cement to 6 parts sand, the mix consists of 7 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet Mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5.
Size of block in consideration is 450mmx 225mm x 225mm blocks.
Calculations:
Materials for mortar composition:
A. Cement: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of cement will (1/7) x 1.20 cubic metres of wet concrete. This gives the volume of 0.17 cubic metres. Using the density 1440 kg/m³, the weight of cement will 0.17 cubic metres x 1440 kg/m³ = 246.86 kg.
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg =4.93 bags ≈ 5 bags.
B. Sand: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of sand required is (6/7) x 1.20 cubic metres = 1.03 cubic metres. The density of Sand is 1600 kg/m³. The weight of sand will be 1.03 cubic metres x 1600 kg/m³ = 1645.71 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.645 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.17 cubic metres x 0.5 = 0.085 cubic metres. When converted to litres, 0.85 cubic metres x 1000 = 85.71 litres.
D. Blocks: The size of the block in consideration is 450mmx 225mm x 225mm blocks. The volume of mortar needed at one end of the one block is gotten by 0.450m x 0.225m x 0.225m = 0.02278125 cubic metres (V1). The Block is added to 25mm thick mortar which give 0.475m x 0.25 x 0.25 which gives a volume of 0.02268125 cubic metres (V1).
The mortar is then added to the blocks with the dimensions 0.45 x 0.225 x 0.25 which give a volume of 0.02671875 cubic metres (V2). There is a void in the two sides in the block that is to be deducted is 2 x 0.15m x .15m x 0.025m=0.001125m³ (D1). The volume of mortar per block is mortar volume per block is the difference between V2 and (V1+D1) = 0.02278125 cubic metres - (0.02671875 cubic metres + 0.001125 cubic metres) = 0.0028125 cubic metres per block. There are 10 blocks in a square metre of block wall and the volume of mortar per square metre for 225 Blockworks is 0.028125 cubic metres per square metre.
For the materials in the mortar per square metre:
10 blocks of 225mm block wall are required per square metre.
The Cement for mortar, in 1 cubic metres of mortar, 4.937142857 bags of 50 kg each are required. For 0.028125 cubic metres per square metre, the amount of cement 0.028125 cubic metres x 4.937142857 =0.13948 bags per square metre.
The required Sand for mortar, in 1 m³ of mortar, 1.64571 tonnes of sand are required. For 0.028125 cubic metres per square metre, the amount of sand 0.028125 cubic metres x 1.64571 = 0.04631 tonnes.
The required water for mortar, for 1 cubic metres of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metres of mortar: Amount of water 0.028125 cubic metres x 85.71litres = 2.4098 litres.
For the service required:
A skilled mason will charge ₦5,000 per day, while a semi-skilled mason is paid ₦3,500 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 5.5 square metre per day): ₦8,500 / 5.5 square metre = ₦1,545.45 per square metre.
Total cost of materials used per square metre
Blocks- 10 blocks make 1 square metre = 10 x 750= ₦7,500.00
Cement- 0.13948 bags x 7,700.00= ₦1,073.99
Sand- 0.04631 x tonnes x 8,000.00 = ₦370.48
Total cost of materials=₦8,944.47
Total cost
The cost of laying an sandcrete block wall per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦8,944.47 (Material costs) and ₦1,545.00 (Service cost) which gives a total of ₦10,489.92.
Schedule for Laying Sandcrete Block Wall:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦9,294.66 per square metre
Service or labour cost per square metre: ₦3,400.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦12,694.66
Entity - Water Feature - Swimming Pool
Entity - Water Feature - Swimming Pool
This refers to activities below the ground. The substructure of a building is everything that is constructed below ground level. It includes all the foundational work needed to support the building and keep it stable.
3.1 Excavation and Fillings
Excavation and fillings in swimming pool construction refer to the process of digging and preparing the ground for the pool's substructure. Excavation involves removing soil, rocks, and debris to create the pool's shape and depth. Fillings are used to stabilize the pool base, backfill around its walls, and ensure proper compaction to prevent shifting. This process provides a solid, level foundation, supports structural integrity, and facilitates effective drainage and waterproofing for the pool.
3.1.1 Site Clearance - Vegetation
Site clearance in the foundation stage of building construction involves removing vegetation, debris, and existing structures to prepare the site for excavation. This includes demolishing old buildings, clearing trees and shrubs, and removing any underground utilities. Site clearance ensures a clean and safe area for construction activities to commence. Additionally, it allows for proper access and layout of the construction site according to architectural and engineering plans. Site clearance sets the stage for the foundation work to begin efficiently.
Assumptions:
The task is to clear a plot of land for construction, the total area of land that needs to be cleared in this scenario 200 square metres.
One unskilled help can clear 20 square metres per day. This involves removing vegetation on the land.
The daily wage for the unskilled help is ₦3,000.00.
Calculations:
The rate per square metre for the unskilled help is calculated as: ₦3,000.00 / 20 square metres = ₦150.00 square metres
To clear 200 square metres, we need to calculate how many days the unskilled help will work: 200 square metres / 20 square metres per day = 10 days
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily wage: 10 days x ₦3,000.00 per day = ₦30,000.00
Schedule for Site Clearance:
Assumed quantities: 200 square metres
Daily output per unskilled help: 20 square metres
Number of days required: 10 days
Daily wage per unskilled help: ₦3,000.00
Total cost for service or labour: ₦30,000.00
Built up rate for labour: ₦150.00 per square metres
3.1.2 Topsoil Excavation
Topsoil excavation in the foundation stage of building construction involves removing the uppermost soil layer, which is rich in organic material and unsuitable for supporting structural loads. This process ensures a stable base for the foundation by eliminating potential settlement and instability caused by the organic content. Excavation typically reaches a depth where the soil is more compact and capable of bearing the structure's weight. The removed topsoil can be stored and reused for landscaping purposes. Properly executed topsoil excavation is critical for establishing a solid, reliable foundation and preventing future structural issues.
Assumptions:
The task is to determine the volume of earth that needs to be excavated, we have to excavate a depth of 0.175 metres of a 200 square metres area of land. The result will get you 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the Unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help is ₦2,200.00
Calculations:
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days
The unit rate is the total cost divided by the service output. That is ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00
Schedule of Topsoil Excavation:
Assumed Quantities: 35 cubic metres
Daily output per unskilled help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
3.1.3 Bulk Excavation
Bulk excavation involves digging narrow, elongated depressions in the ground to prepare for foundation footings, utility lines, and drainage systems. This process requires precise measurements and careful planning to ensure proper depth, width, and alignment. Excavated soil is typically stored nearby for backfilling. Safety measures, like trench shoring or shielding, are essential to prevent collapses and protect workers. Once the trench is prepared, it serves as a stable base for laying the building's foundation elements, ensuring structural integrity and proper support for the overall construction.
Assumptions:
The task is to determine the volume of earth soil in the trench that needs to be excavated. For example, let's say you need to excavate a trench of with a total volume of 35 cubic metres.
One unskilled help can excavate 3.5 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help, including tools, is ₦2,200.00
Calculations:
Each day, the unskilled help will have an output of work 3.5 cubic metres of earth.
The unit rate is the total cost divided by the service output. ₦2,200.00 / 3.5 cubic metres = ₦628.57 per cubic metres.
To excavate 35 cubic metres, calculate how many days the unskilled help will need: 35 cubic metres / 3.5 cubic metres per day = 10 days.
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000.00.
Schedule for Trench Excavation:
Assumed quantities to excavate: 35 cubic metres
Daily output per unskilled Help: 3.5 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦628.57 per cubic metre
3.1.4 Pour Backfill to Trench Excavation
In the foundation stage of building construction, pouring backfill into trench excavations involves refilling and compacting the void left after excavation with suitable materials like soil or gravel. This serves to provide support to the foundation, enhancing its stability and preventing settlement. Backfilling also helps in improving drainage around the foundation and protects against soil erosion. Proper compaction of the backfill material is essential to ensure uniform support and minimize future settlement.
Assumptions:
The task is to determine the volume of earth that needs to be backfilled to the sides of excavation. For example, let's say you need to backfill 40 cubic metres.
Calculations:
One unskilled help can backfill 4 cubic metres per day.
The daily wage for the unskilled help is ₦2,200.00
Therefore, the total cost per day for the unskilled help is ₦2,200.
To backfill 40 cubic metres, calculate how many days the unskilled help will need: 40 cubic metres / 4 cubic metres per day = 10 days
The total cost for labour over the entire period is calculated by multiplying the number of days by the daily cost: 10 days x ₦2,200 per day = ₦22,000
Cost per cubic metre is ₦22,000/40 cubic metres = ₦550 per cubic metres.
Schedule for Pouring Backfill to Trench Excavation:
Assumed quantities to backfill: 40 cubic metres
Daily output per unskilled help: 4 cubic metres
Number of days required: 10 days
Daily wage per unskilled help: ₦2,200.00
Total cost per day: ₦2,200.00
Total cost for service or labour: ₦22,000.00
Built up rate: ₦550 per cubic metre
3.1.5 Disposal (On-Site)
On-site disposal in building construction involves managing and disposing of excavated soil, debris, or waste materials within the construction site itself. This process requires designated areas for temporary storage, sorting, and proper disposal methods, such as recycling or landfilling. On-site disposal helps minimize transportation costs and environmental impact by reducing the need for off-site hauling. Effective on-site disposal practices contribute to efficient project management and sustainable construction practices, ensuring responsible waste management throughout the building process.
Assumptions:
The task is to determine the volume of excavated materials that needs to be disposed to a spoil heap 1 metre away, assuming the volume of excavated material is 20 cubic metres.
Disposal volume: Workers can handle 4 cubic metres of disposal per day.
Service Cost: It costs ₦2,200.00 for the unskilled help each day.
Calculations:
One unskilled unskilled help can backfill 4 cubic metres per day.
Unit rate: To find the unit rate per cubic metre, divide the total cost by the labour output: ₦2,200 / 4 cubic metres = ₦550 per cubic metres.
To dispose of 20 cubic metres, calculate how many days the unskilled unskilled help will need: 20 cubic metres / 4 cubic metres per day = 5 days.
The total cost for labour and tools over the entire period is calculated by multiplying the number of days by the daily cost: 5 days x ₦2,200 per day = ₦11,000.00.
Schedule for On-Site Disposal:
Assumed quantities to dispose: 20 cubic metres
Daily output per unskilled help: 4 cubic metres
Unskilled help wages per Day: ₦2,200.00
Total cost for service or labour: ₦11,000.00
Built up rate: ₦550 per cubic metre
3.1.6 Task Disposal (Off-Site)
Off-site disposal is an aspect of the construction process where excavated soil, debris, or waste materials generated during site preparation, excavation, or demolition are transported and disposed of at designated facilities away from the construction site. This involves loading the materials onto trucks or containers and transporting them to licensed disposal sites or recycling facilities. Off-site disposal ensures proper waste management, environmental protection, and compliance with regulations. It also helps maintain a clean and safe construction site, minimizing environmental impact and ensuring the efficient progress of the construction project.
Assumptions:
The task is to determine the volume of excavated materials that need to be disposed of. For example, let's say you need to dispose of 10 cubic metres of excavated earth.
One Unskilled help can load the disposal of 3.82 cubic metres per day averagely.
A 5 tonne Truck can transport 3.82 cubic metres of excavated materials per trip within a 5km radius. The transportation cost per lorry is ₦25,000.00.
Calculations:
To determine the service cost: Output of Unskilled help per day: 3.82 cubic metres.
Unskilled help wages per day: ₦3,000.00
Total Unskilled help cost for 3.82 cubic metres: ₦3,000.00 / 3.82 cubic metres = ₦785.34.
For the Transportation cost: One Truck lorry transports 3.82 cubic metres per 5km radius, the transportation cost per lorry: ₦25,000.00.
To dispose 10 cubic metres, calculate how many days the unskilled help will need: 10 cubic metres / 3.82 cubic metres per day = 2.61= 3 days.
Transportation cost per cubic metres: ₦25,000.00 / 3.82 cubic metres = ₦6,544.50 per cubic metres.
The total cost per cubic metre, including both labour and transportation, is ₦785.34 + ₦6,544.50 = ₦7,329.84 per cubic metres.
Schedule for Disposal Off-Site:
Assumed quantities to dispose: 10 cubic metres
Daily output per unskilled help: 3.82 cubic metres
Unskilled help wages per cubic metres: ₦785.34
Transportation cost per cubic metres: ₦6,544.50
Built up rate per cubic metres: ₦7,329.84
3.1.7 Pour Fillings (Laterite Sand Fillings)
Laterite sand fillings involve pouring and compacting layers of laterite sand. This material, rich in iron and aluminum oxides, provides excellent load-bearing capacity and drainage properties. The compacted fillings ensure uniform support beneath the foundation, minimizing settlement and structural issues. Proper compaction techniques, such as mechanical compaction or wetting and rolling, are employed to achieve the required density. Laterite sand fillings create a stable base for the foundation, contributing to the structural integrity and longevity of the building.
Assumptions:
The task is to determine the volume of lateritic sand needed to fill and make up the levels. For example, let's say you need to fill 25 cubic metres.
The material cost of 1 cubic metre of lateritic sand is ₦7,000.00. Adding 50% for shrinkage and waste amounts to ₦3,500.00, making the total ₦10,500.00 per cubic metres.
The rental of a compactor (tamper) costs ₦50,000.00.
The daily wage for the unskilled help is ₦2,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of lateritic sand is ₦10,500 per cubic metre, this includes the shrinkage and waste.
The compactor (tamper) costs ₦50,000.00 and can ramp up to 5 cubic metres per day. The equipment cost per cubic metre is ₦50,000.00 / 5 cubic metres = ₦10,000.00 per cubic metre.
One unskilled help can handle 2 cubic metres per day. The daily wage for the unskilled help is ₦2,400.00, the labour cost per cubic metre is ₦2,400.00 / 2 = ₦1,200.00 per cubic metre.
To pour 25 cubic metres, calculate how many days the unskilled help will need: 25 cubic metres / 2 cubic metres per day = 12.5 days or 13 days.
The total cost per cubic metre, including materials, equipment, and labour, is ₦10,500 (materials) + ₦10,000.00 (equipment) + ₦1,200.00 (labour) = ₦21,700.00 per cubic metre.
Schedule for Pouring Fillings (Laterite Sand Fillings):
Assumed quantities to fill: 25 cubic metres
Daily output per unskilled help: 2 cubic metres
Unskilled help wages per day: ₦2,400.00
Total cost per day for unskilled help: ₦2,400.00
Labour cost per cubic metre: ₦1,200.00
Material cost per cubic metre: ₦10,500.00
Equipment cost per cubic metre: ₦10,000.00
Built up rate per cubic metre: ₦21,700.00
3.1.8 Pour Fillings (Sharp Sand Fillings)
Pouring sharp sand fillings involves depositing and compacting sharp sand within the excavated area. This process aims to create a stable and level base for the foundation. Sharp sand, with its angular particles, facilitates good compaction and drainage properties, ensuring uniform support for the structure above. By eliminating voids and providing a solid substrate, sharp sand fillings enhance the load-bearing capacity of the foundation, contributing to the overall stability and durability of the building. Proper compaction techniques are employed to achieve the desired density and uniformity of the sand fillings.
Assumptions:
The task is to determine the volume of Sharp sand needed to fill and make up the levels. For example, let's say you need to fill 25 cubic metres.
The material cost of 1 cubic metre of Sharp sand is ₦6,500.00. Adding 30% for shrinkage and waste amounts to ₦1,950.00, making the total ₦8,450.00 per cubic metres.
The daily wage for the unskilled help is ₦3,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of lateritic is ₦8,450 per cubic metre, this includes the shrinkage and waste.
One unskilled help can handle 2 cubic metres per day. The daily wage for the help is ₦3,400.00, the labour cost per cubic metre is ₦3,400.00 / 2 cubic metres = ₦1,700.00 per cubic metre.
To pour 25 cubic metres, calculate how many days the unskilled help will need: 25 cubic metres / 2 cubic metres per day = 12.5 days.
The total cost per cubic metre, including materials and labour, is ₦8,450 (materials) + ₦1,700.00 (labour) = ₦11,150.00 per cubic metre.
Schedule for Pouring Fillings (Sharp Sand Fillings):
Assumed quantities to fill: 25 cubic metres
Daily output per unskilled help: 2 cubic metres
Unskilled help wages per day: ₦3,400.00
Total cost per day for unskilled help: ₦1,200.00
Labour cost per cubic metre: ₦1,700.00
Material cost per cubic metre: ₦8,450.00
Built up rate per cubic metre: ₦11,150.00
3.1.9 Pour Fillings (Hardcore Stone fillings)
Hardcore stones filling, a crucial step in the foundation stage of building construction, involves filling and compacting layers of coarse aggregates like gravel or crushed stones. This process creates a stable and load-bearing base for the foundation. By evenly distributing the weight of the structure and providing adequate drainage, hardcore stones prevent settling or shifting over time, ensuring the structural integrity and longevity of the building. Proper compaction techniques are employed to achieve the desired density, maximizing the effectiveness of the hardcore stones in supporting the foundation and ultimately the entire building.
Assumptions:
The task is to determine the volume of Hardcore Stones needed to fill and make up the levels. For example, let's say you need to fill 10 cubic metres.
The material cost of 1 cubic metre of Hardcore Stones is ₦16,500.00. Adding 5% for waste amounts to ₦825.00, making the total ₦17,325.00 per cubic metres.
The daily wage for the unskilled help is ₦3,400.00 and one unskilled help can handle 2 cubic metres per day.
Calculations:
The total material cost of Hardcore Stones is ₦17,325.00 per cubic metre, this includes the 5% waste.
One unskilled help can handle 1 cubic metres per day. The daily wage for the help is ₦3,000.00, the labour cost per cubic metre is ₦3,000.00 / 1 = ₦3,000.00 per cubic metre.
To pour 10 cubic metres, calculate how many days the unskilled help will need: 10 cubic metres / 1 cubic metre per day = 10 days
The total cost per cubic metre, including materials and labour, is ₦17,325.00 (materials) + ₦3,000.00 (labour) = ₦20,325.00 per cubic metre.
Schedule for Pouring Fillings (Hardcore Stones):
Assumed quantities to fill: 10 cubic metres.
Daily output per unskilled help: 1 cubic metre
Unskilled help wages per day: ₦3,000.00
Total cost per day for unskilled help: ₦3,000.00
Labour cost per cubic metre: ₦3,000.00
Material cost per cubic metre: ₦17,325.00
Built up rate per cubic metre: ₦20,325.00
3.2 In-Situ Concrete
In-situ concrete refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
3.2.1 Reinforcement Works
Reinforcement works in the foundation stage of building construction involve the arrangement and placing of steel bars (rebar) or mesh in preparation for concrete casting, to enhance its tensile strength. This process starts with designing the reinforcement layout according to structural requirements. Rebars are then cut, bent, and placed in formwork according to design specifications. These steel reinforcements are secured with ties or clips to maintain position during concrete pouring. Reinforcement in foundation concrete provides greater load-bearing capacity, prevents cracking under stress, and ensures the stability and longevity of the building by distributing loads more evenly across the structure.
3.2.1.1 Install Reinforcement in Pool Base Slab
Steel rebar cages, prefabricated with vertical and horizontal bars, are lowered into the excavated column base. They're secured in place using spacers to maintain precise positioning within the concrete. These cages create a strong internal skeleton for the column bases, enabling them to transfer the building's weight properly to the soil.
Assumptions:
The task is to Install reinforcement steel bars in column bases and column starter. The materials used are reinforcement steel bars and binding wires. The standard length of reinforcement steel bars is 12 metres. The steel bars have the different diameters ranging from 32mm to 8mm. The standard size of binding wire is 20kg per roll.
Calculations:
For Different sizes of reinforcement steel bars:
A. 32mm Steel bar:
Weight per metre: 6.318 kg
Weight per 12m bar: 6.318 kg/m x 12m = 75.816 kg
Number of bars per tonne: 1 tonne / 75.816 kg ≈ 13 bars
B. 25mm Steel Bar:
Weight per metre: 3.856 kg
Weight per 12m bar: 3.856 kg/m x 12m = 46.272 kg
Number of bars per tonne: 1 tonne / 46.272 kg ≈ 22 bars
C. 20mm Steel bar:
Weight per metre: 2.468 kg
Weight per 12m bar: 2.468 kg/m x 12m = 29.616 kg
Number of bars per tonne: 1 tonne / 29.616 kg ≈ 34 bars
D. 16mm Steel bar:
Weight per metre: 1.58 kg
Weight per 12m bar: 1.58 kg/m x 12m = 18.96 kg
Number of bars per tonnes: 1 tonne / 18.96 kg ≈ 53 bars
E. 12mm Steel Bar:
Weight per metre: 0.888 kg
Weight per 12m bar: 0.888 kg/m x 12m = 10.656 kg
Number of bars per ton: 1 tonne / 10.656 kg ≈ 94 bars
F. 10mm Steel bar:
Weight per metre: 0.617 kg
Weight per 12m bar: 0.617 kg/m x 12m = 7.404 kg
Number of bars per ton: 1 tonne / 7.404 kg ≈ 135 bars
G. 8mm Steel bar:
Weight per metre: 0.395 kg
Weight per 12m bar: 0.395 kg/m x 12m = 4.74 kg
Number of bars per ton: 1 tonne / 4.74 kg ≈ 211 bars
2. Binding wire:
Weight per roll: 20 kg
Quantity required per ton of steel bars: 12 kg
Number of rolls required per tonne: 12 kg / 20 kg per roll = 0.6 rolls per tonne
Cost of binding wire per tonne of reinforcement bars: ₦42,000 x 0.6 = ₦25,200
Daily equipment rentals calculations:
Cutting machine: ₦50,000.00 per day
Angle grinder: ₦25,000.00 per day
Rebar bender (Electric): ₦150,000.00 per day
Total equipment Cost: ₦225,000.00per day
Average productivity: 1 tonnes per day
Equipment cost per tonne: ₦225,000.00
Service:
Iron bender skilled: ₦10,000.00 per day
Iron bender semi-Skilled Placer: ₦7,500.00 per day
Iron bender semi-Skilled: ₦7,500.00 per day
Total service cost: ₦25,000.00 per day
Average productivity: 1 tonne per day
Service cost per tonne: ₦25,000.00
Total installation cost per tonne:
This includes materials, equipment, and service costs. The exact cost depends on the size of the steel bars used. For example, if using 20mm steel bars:
Material Cost: Cost of steel bars ₦1,200,000.00 + (10% waste ₦120,000.00 )+ binding wire cost )
= (₦1,200,000.00 + 120,000.00 + ₦25,200.00)
= ₦1,345,200.00
Total Cost per tonne = Material Cost + 225,000.00 (equipment) + 25,000.00 (service)
= ₦1,345,200.00 + ₦225,000.00 + ₦25,000.00
= ₦1,595,200.00 per tonne
Schedule for Installing Reinforcement in Column Bases:
Assumed quantity: 1 tonne
Total material cost per tonne: ₦1,345,200.00
Equipment cost per tonne: ₦225,000.00
Service cost per tonne: ₦25,000.00
Total cost per tonne: ₦1,595,200.00 per tonne
3.2.1.2 Installing Reinforcement in Pool Wall
During foundation work, steel rods (rebar) are bent at their ends and placed strategically within the concrete footing. These hooked bars act as anchors. When the columns are erected later, they slot over these anchors, creating a secure connection. This ensures the columns can effectively transfer the building's weight down to the foundation.
Refer to the calculations in 3.2.1.1
3.2.3 Concrete Works
In-situ concrete works refers to concrete that is mixed, poured, and cured directly at the construction site. It is used for the creation of strong, continuous structural elements such as foundations, walls, and slabs, tailored precisely to the design specifications of the building. It provides flexibility in shaping complex forms and integrates well with other construction processes. In-situ concrete ensures robust, monolithic structures, contributing to the overall stability and durability of the building while allowing for customized architectural features.
3.2.3.1 Pour Concrete into Blinding
Pouring concrete for blinding involves applying a thin layer of low-grade concrete over the prepared surface of the excavated area. This serves as a base to protect the underlying soil from contamination and to provide a level surface for subsequent construction activities. Blinding concrete also acts as a moisture barrier and helps in preventing the upward migration of groundwater. It ensures a stable foundation for the building structure and facilitates proper bonding with subsequent layers of concrete or the installation of foundation elements.
Assumptions:
The tasks involves pouring of concrete in 1 cubic metre of blinding to earth with the details below
Concrete mix ratio: Cement to Sand to Granite is 1:6:9.
Total portions: The mix consists of 16 parts.
Void in aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed.
Water cement ratio: The water-cement ratio is 0.5.
The output of the Workers is 2 cubic metres daily.
The daily rental cost of a concrete mixer is ₦120,000.00.
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg =2.77 bags ≈ 3 bags
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 = 0.924 Tonne
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 Tonnes
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625cubic metres x 0.5 = 0.048125 cubic metres. When converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250.00 per cubic metres.
Equipment Used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000.00 per cubic metres
The total cost of materials per cubic metre:
Cement: 3 bags = 3 x 7,700 per bag = ₦23,100.00
Sand: 0.924 tonnes = 0.924 x 8,000 per tonne = ₦7,392.00
Granite: 1.472 tonnes = 1.472 x 13,000 per tonne = ₦19,136.00
Water: 48.125 litres (covered or measured under the preliminary items)
Total cost of materials = ₦49,628.00
Total cost per cubic metre of concrete (Grade 10):
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦49,628.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦113,878.00
Schedule for Pour Concrete into Blinding:
Assumed quantities: 1 cubic metre
Total material cost per cubic metre: ₦49,628.00
Service or labour cost per cubic metre: ₦4,250.00
Equipment cost per cubic metre: ₦60,000.00
Total cost of concrete in blinding: ₦113,878.00
3.2.3.2 Pour Concrete into Pool Base Slab Section
Pouring concrete into the pool base slab section refers to the process of casting a solid concrete foundation for the pool. As part of in-situ concrete work under the substructure, it involves mixing, transporting, and pouring concrete into the prepared base form. The slab provides structural support for the pool, ensuring stability and preventing settling. The process includes reinforcement installation, ensuring proper curing and leveling, and achieving the required thickness and strength for long-term durability.
Assumptions:
Concrete Mix Composition:
The task involves pouring of concrete in 1 cubic metre of concrete in column base, column starter and concrete slab.
Ratio: Cement to Sand to Granite is 1:2:4.
Total Portions: The mix consists of 7 parts.
Void in Aggregates: There is a 54% void in the aggregates to account for material shrinkage and waste.
Mix Volumes: To prepare 1 cubic metre of wet concrete, 1.54 cubic metres of dry concrete is needed.
Water Cement Ratio: The water-cement ratio is 0.5.
The output of the Workers is 2 cubic metres daily.
The daily rental cost of a concrete mixer is ₦120,000.00.
Calculations:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/7) = 0.22 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of cement will be 0.22 cubic metres x 1440 kg/m³ = 316.8 kg. The number of bags of cement is (50 kg each): 316.8 kg / 50 kg =2.77 bags ≈ 7 bags
B. Sand: The volume of sand required is 1.54 cubic metres x (2/7) = 0.44 cubic metres. The density of Sand is 1600 kg/m³. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The mass of sand will be 0.44 cubic metres x 1600 kg/m³ = 704 kg. The weight of Sand in tonnes is 704 kg / 1000 =0. 704 Tonne
C. Granite: The volume of granite required is 1.54 cubic metres x (4/7) = 0.88 cubic metres. To get the mass of Cement, we will multiply the volume by the density. The density of Sand is 1600 kg/m³.The density of granite is 1700 kg/m³. The mass of granite will be 0.88 cubic metres x 1700 kg/m³ = 1496 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.496 Tonnes
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.22 cubic metres x 0.5 = 0.11 cubic metres. When converted to litres, 0.11 cubic metres x 1000 = 110 litres
For the service required:
A skilled mason will charge ₦5,000 per day, while a semi-skilled mason is paid ₦3,500 per day. The total cost of labour is ₦8,500 per day. The labour cost per cubic metre (assuming 2 cubic metres per day): ₦8,500 / 2 = ₦4,250 per cubic metre.
Equipment used:
For the concrete mixer rental: The daily rental cost: ₦120,000.00. The daily production capacity is 2 cubic metres. The equipment cost per cubic metre: ₦120,000 / 2 = ₦60,000 per cubic metres
The total cost of materials per cubic metre:
Cement: 7 bags = 7 x 7,700 per bag =₦53,900.00
Sand: 0.704 tonnes = 0.704 x 8,000= ₦5,632.00
Granite: 1.496 tonnes= 1.496 x 13,000.00=₦19,448.00
Water: 110 litres (covered or measured under the preliminary items)
Total cost of materials =₦78,980.00
The total cost per cubic metre of concrete Grade 15:
The total cost for pouring 1 cubic metre of concrete includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦78,980.00 (Material costs), ₦4,250.00 (Service cost) and ₦60,000.00 (Equipment cost) which gives a total of ₦143,230.00
Schedule for Pour Concrete into Column Bases:
Total material cost per cubic metre: ₦78,980.00
Service or labour cost per cubic metre: ₦4,250
Equipment cost per cubic metre: ₦60,000
Total cost of concrete in blinding: ₦143,230.00
3.2.3.3 Pour Concrete into Pool Wall
Pouring concrete into a pool wall as part of in-situ concrete under substructure involves casting concrete directly on-site within formwork to create the pool's vertical walls. This process ensures a seamless, strong, and watertight structure. It includes setting up formwork, placing steel reinforcement, and pouring wet concrete into the mold. Once cured, it provides a durable, load-bearing surface. This method is preferred for custom pool shapes and ensures precise alignment with the pool design.
Refer to the calculations in 3.2.3.2
3.2.4. Formwork for In-Situ Concrete
Formwork for in-situ concrete is a temporary mold into which concrete is poured and shaped during construction. It provides support until the concrete hardens and gains sufficient strength to support itself. Typically made from materials like timber, plywood, steel, or aluminum, formwork ensures accurate dimensions and surface finish of structural elements such as walls, columns, and slabs. It must be sturdy, leak-proof, and easy to remove once the concrete sets. Proper formwork design and installation are crucial for structural integrity, safety, and efficient construction progress, impacting the quality and durability of the final structure.
3.2.4.1 Fix Formwork to Pool Base Slab
Fixing formwork to the pool wall in the context of swimming pool construction refers to the process of securing temporary molds (formwork) to the pool's walls. These molds define the shape and dimensions of the concrete structure. Once fixed in place, they ensure the concrete sets correctly, providing structural support and stability for the pool walls. This step is essential before pouring the concrete to form the permanent walls of the pool.
Assumptions:
The task involves fixing formwork to sides of pool base slabs. The proposed area to be covered by formwork is 30 square metres.
The formwork to be used Marine board and Hardwood
Marine board size: 1.2 x 2.4 metres (2.88 m²), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used.
Calculations:
Materials required:
A. Marine board: the area of the size is (2.88 m²), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00.
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00.
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 11 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00.
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 square metre = ₦5,520.00 per square metre.
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metre.
For the service required:
A skilled Carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000.00 per day. The labour output is 15 square metres per day, the cost per square metre is ₦9,000 / 15 m² = ₦600.00 per square metre.
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 m². The equipment cost per square metre is ₦12,000 / 15 square metre = ₦800.00 per square metre.
Total cost:
The total cost for per square metre of fixing formwork to sides of the pool base slabs includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00 per square metre and equipment cost ₦800.00/m²which gives ₦3,240.00 per square metre. The formwork to sides of the pool base slabs is measured in linear metre with an average height of 500mm. This gives the cost per linear metre to be ₦3,240.00 per square metre x 0.5m making ₦1,620.00 the cost per linear metre.
Schedule for Formwork in Pool Base Slab:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
Built up rate per linear metre : ₦1,620.00 per metre
1.2.4.2 Fix Formwork to Sides of Pool Wall
Fixing formwork to the pool wall in the context of swimming pool construction refers to the process of securing temporary molds (formwork) to the pool's walls. These molds define the shape and dimensions of the concrete structure. Once fixed in place, they ensure the concrete sets correctly, providing structural support and stability for the pool walls. This step is essential before pouring the concrete to form the permanent walls of the pool.
Assumptions:
The task involves fixing formwork to the sides of pool walls. The proposed area to be covered by formwork is 30 square metres
The formwork to be used Marine board and Hardwood:
Marine board size: 1.2 x 2.4 metres (2.88 square metres), Hardwood size 50 x 100 x 3.6 metres
Cost per piece of marine boards: ₦11,000.00
Cost per piece of Hardwood: ₦650.00
Circular saw is the equipment used.
Calculations:
A. Marine board: the area of the size is (2.88 square metres), to cover 30 metres square, 30 / 2.88 = 10.41, rounded up to 11 boards. The total cost for marine boards is 11 x ₦11,000.00 = ₦121,000.00
B. Hardwood: from site data, 4 pieces of 50 x 100 x 3.60m hardwood is used per marine board averagely, the total pieces needed is 11 boards x4 pieces = 44 pieces. The total cost for 50 x 100 hardwood: 44 x ₦650.00 = ₦28,600.00
C. Nails: 0.9 kg of wire nails is used to nail per marine board as the constant, the total nails needed is 1 boards x 0.9 kg = 9.9 kg, rounded to 10 kg. The total cost for nails: 10 x ₦1,600.00 = ₦16,000.00
Total material cost:
The total cost for the use of marine board as formwork is ₦121,000.00 (boards) + ₦28,600.00 (hardwood) + ₦16,000.00 (nails)
= ₦165,600.00.
The material cost per square metre: ₦165,600 / 30 m² = ₦5,520.00 per square metres.
Assuming the formwork can be reused thrice: ₦5,520 / 3 = ₦1,840.00 per square metres.
For the service required:
A skilled carpenter will charge ₦6,000 per day, while a semi-skilled carpenter is paid ₦3,000 per day. The total cost of labour is ₦9,000 per day. The labour output is 15 square metres per day, per square metre is ₦9,000 / 15 square metres = ₦600.00/m².
Equipment used:
For the circular saw rental: The daily rental cost: ₦12,000.00. The daily production capacity is 15 per square metre . The equipment cost per cubic metre is ₦12,000.00 / 15 square metre = ₦800.00 per square metre.
Total cost:
The total cost for per square metre of fixing formwork to sides of the pool wall includes the cost of materials, labour, and equipment. Total cost is the addition of the cost per square metre of material costs of ₦1,840.00 per square metre, service cost of ₦600.00/m² and equipment cost ₦800.00 per square metre which gives ₦3,240.00 per square metre.
Schedule for Formwork to Sides of Pool Wall:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦5,520.00 per square metre
Service or labour cost per square metre: ₦600.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦3,240.00 per square metre
3.3. Masonry
Masonry involves the assembly of individual units like bricks, stones, or concrete blocks, bound together by mortar. It is used to build structures such as walls, foundations, and columns. Masonry offers durability, fire resistance, and aesthetic appeal, making it a popular choice for both structural and decorative purposes. The process requires skilled labor to ensure precise alignment and stability. Proper masonry construction provides excellent load-bearing capacity, thermal insulation, and soundproofing, contributing significantly to the overall integrity and functionality of a building.
3.3.1 Lay Hollow Filled Sandcrete Block Wall
Once the foundation trench has been prepped, leveled, and filled with concrete to create a footing, a crew lays a flat course of mortar. Sandcrete blocks are meticulously stacked on the mortar, then filled with concrete to increase its strength. Each block is checked for level and plumb, with a thin mortar layer spread before placing the next course. Staggering the block joints, row by row, builds a strong, interlocking foundation wall. This precise process continues until the entire foundation reaches its planned height.
Assumptions:
The task involves laying of hollow filled sandcrete blocks for 1 square metre of block wall.
Mortar mix ratio: Cement to Sand is 1:6, 1 part cement to 6 parts sand, the mix consists of 7 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet Mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5.
Size of block in consideration is 450mmx 225mm x 225mm blocks
Calculations:
Materials for mortar composition:
A. Cement: The cement to sand ratio 1:6 (1 part cement to 6 parts sand). The volume of cement will (1/7) x 1.20 cubic metres of wet concrete. This gives the volume of 0.17 cubic metres. Using the density 1440 kg/m³, the weight of cement will 0.17 cubic metres x 1,440 kg/m³ = 246.86 kg.
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg =4.93 bags ≈ 5 bags.
B. Sand: The cement to sand ratio 1:6 (1 part cement to 6 parts sand).The volume of sand required is (6/7) x 1.20 cubic metres = 1.03 cubic metres. The density of Sand is 1600 kg/m³. The weight of sand will be 1.03m³ x 1600 kg/m³ = 1645.71 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.645 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.17 cubic metres x 0.5 = 0.085 cubic metres. When converted to litres, 0.85 cubic metres x 1000 = 85.71 litres.
D. Blocks: The size of the block in consideration is 450mmx 225mm x 225mm blocks. The volume of mortar needed at one end of the one block is gotten by 0.450m x 0.225m x 0.225m = 0.02278125 cubic metres (V1). The mortar is then added to the blocks with the dimensions 0.45 x 0.225 x 0.25 which give a volume of 0.02671875 cubic metres (V2). There is a void in the two sides in the block that is to be deducted is 2 x 0.15m x .15m x 0.025m=0.001125 cubic metres (D1). The volume of mortar per block is mortar volume per block is the difference between V2 and (V1+D1) = 0.02671875 cubic metres - (0.02671875 cubic metres + 0.001125 cubic metres) = 0.0028125 cubic metres per block. There are 10 blocks in a square metre of block wall and the volume of mortar per square metre for 225 blockworks is 0.028125 cubic metres per square metre.
For the materials in the mortar per square metre
10 blocks of 225mm block wall are required per square metre.
The Cement for mortar, In 1 cubic metres of mortar, 4.937142857 bags of 50 kg each are required. For 0.028125 cubic metres per square metre, the amount of cement 0.028125 m³ x 4.937142857 =0.13948 bags per square metre.
The required Sand for mortar, in 1 cubic metre of mortar, 1.64571 tonnes of sand are required. For 0.028125 cubic metre per square metre, the amount of sand 0.028125 cubic metres x 1.64571 = 0.04631 tonnes.
The required water for mortar, for 1 cubic metres of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metres of mortar: Amount of water 0.028125 cubic metres x 85.71litres = 2.4098 litres.
For the plain concrete 1:6:9 poured in block wall:
Materials required:
A. Cement: The volume of cement required is 1.54 cubic metres x (1/16) = 0.09625 cubic metres. The cement density is 1440 kg/m³. To get the mass of Cement, we will multiply the volume by the density. The mass of cement will be 0.09625 cubic metres x 1440 kg/m³ = 138.6 kg. The number of bags of cement is (50 kg each): 138.6 kg / 50 kg = 2.77 bags ≈ 3 bags.
B. Sand: The volume of sand required is 1.54 cubic metres x (6/16) = 0.5575 cubic metres. To get the mass of Sand, we will multiply the volume by the density. The density of Sand is 1600 kg/m³. The mass of sand will be 0.5575 cubic metres x 1600 kg/m³ = 924 kg. The weight of Sand in tonnes is 924 kg / 1000 =0. 924 tonne.
C. Granite: The volume of granite required is 1.54 cubic metres x (9/16) = 0.86625 cubic metres. To get the mass of Granite, we will multiply the volume by the density. The density of granite is 1700 kg/m³. The mass of granite will be 0.86625 cubic metres x 1700 kg/m³ = 1472 kg. The weight of granite in tonnes is 1472 kg / 1000 = 1.472 tonnes.
D. Water: The water cement ratio for concrete is 0.5. The volume required is 0.09625 cubic metres x 0.5 = 0.048125 cubic metres, when converted to litres, 0.048125 cubic metres x 1000 = 48.13 litres.
For the materials in the mortar per square metre:
The volume of the void concrete will fill per block is 0.001125m³. for 10 blocks of 225 x 450mm block wall are required 0.01125 cubic metres of concrete is required per square metre.
The Cement for concrete, in 1 cubic metres of concrete, 3 bags of 50 kg each are required. For 0.01125m³ per square metre, the amount of cement 0.01125 cubic metres x 3 bags =0.03375 bags per square metre.
The required Sand for concrete, in 1 cubic metres of concrete, 0.924 tonnes of sand are required. For 0.028125 cubic metre/square metre, the amount of sand 0.01125 cubic metres x 0. 924 = 0.010395 tonnes.
The required granite, in 1 cubic metre of concrete, 1.472 tonnes of Granite is required, the amount of granite 0.01125 cubic metre x 1.472 = 0.01656 tonnes.
The required water for concrete, for 1 cubic metre of mortar, approximately 85.71 litres of water are needed, For 0.028125 cubic metre of mortar: Amount of water 0.028125 cubic metre x 85.71litres = 2.4098 litres.
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500.00 per day. The labour cost per cubic metre (assuming 5.5 square metre per day): ₦8,500.00 / 2.5 square metres = ₦3,400.00 per square metre.
Total cost of materials used per square metre
Blocks - 10 blocks make 1 square metre = 10 x 750= ₦7,500.00
Cement - 0.13948 + 0.03375 = 0.17323 bags x 7,700.00= ₦1,338.87
Sand - 0.04631 + 0.010395 = 0.056705 tonnes x 8,000.00 = ₦453.64
Granite - 0.01656 tonnes = 0.01656 tonnes x 13,000.00= ₦215.28
Total cost of materials = ₦9,294.66
Total cost
The cost of laying an hollow filled Sandcrete block wall per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦9,294.66 (Material costs) and ₦3,400.00 (Service cost) which gives a total of ₦12,694.66
Schedule for Hollow Filled Sandcrete Block Wall:
Assumed quantities: 1 square metre
Total material cost per square metre: ₦9,294.66 per square metre
Service or labour cost per square metre: ₦3,400.00 per square metre
Equipment cost per square metre: ₦800.00 per square metre
Built up rate per square metre: ₦12,694.66
3.6 Floor, Wall and Ceiling Finishings
In swimming pool construction, wall finishes and floor finishes under substructure refer to the final surfaces applied to the pool's walls and floor after the basic structure is built. Wall finishes include materials like plaster, tiles, or aggregate coatings, which ensure smooth, durable, and waterproof surfaces. Floor finishes cover the pool's base, typically with similar materials, ensuring slip resistance, watertightness, and aesthetics. Both finishes contribute to the pool’s longevity and safety.
3.6.1 Cement Sand Screeded Bed on Pool Wall and Pool Base Slab
The subfloor is prepped, ensuring levelness. A cement-sand mix is then poured and meticulously smoothed with a long straightedge to create a perfectly flat screed. This provides a stable and even base for the final floor finish. The thickness of the screed depends on the floor covering (tiles require a thinner layer than carpet) and any underfloor features like radiant heating. Once cured, the screed is ready for the chosen floor finish to be installed, transforming the raw space into a beautiful and functional floor.
Assumptions:
The tasks involves pouring of cement sand screeded bed for floor finish
Mortar mix ratio: Cement to Sand is 1:3, 1 part cement to 4 parts sand, the mix consists of 4 parts.
Void in aggregates: There is a 20% void in the sand to account for material shrinkage and waste.
Mix volumes: To prepare 1 cubic metre of wet Mortar, 1.20 cubic metres of dry mortar is needed.
Water cement ratio: The water-cement ratio is 0.5
The bedding thickness of 36 mm
Calculations:
Materials for screeded bed composition:
A. Cement: The cement to sand ratio 1:3 (1 part cement to 4 parts sand). The volume of cement will (1/4) x 1.20m³ of wet concrete. This gives the volume of 0.30 m³. Using the density 1440 kg/m³, the weight of cement will 0.30 m³ x 1440 kg/m³ = 432 kg
The number of bags of cement is (50 kg each): 246.86 kg / 50 kg = 8.64 bags ≈ 9 bags
B. Sand: The cement to sand ratio 1:4 (1 part cement to 4 parts sand). The volume of sand required is (3/4) x 1.20 cubic metres = 0.90 m³. The density of Sand is 1600 kg/m³. The weight of sand will be 0.90m³ x 1600 kg/m³ = 1440 kg. The weight of Sand in tonnes is 1645.71 kg / 1000 =1.440 tonnes.
C. Water: The water cement ratio for concrete is 0.5. The volume required is 0.3 cubic metres x 0.5 = 0.15 cubic metres. When converted to litres, 0.15 cubic metres x 1000 = 150 litres.
For the materials in the mortar per square metre:
The average bedding thickness for a bedding thickness of 36 mm (or 0.036 metres), the volume required per square metre is 0.036 m³/m².
The Cement for mortar, In 1 m³ of mortar, 9 bags of 50 kg each are required. For 0.036 m³/m², the amount of cement 0.036 m³/m² x 9 bags = 0.324 bags/m²
The required Sand for mortar, In 1 m³ of mortar, 1.440 tonnes of sand are required. For 0.036 m³/m², the amount of sand 0.036 m³ x 1.440 = 0.05184 tonnes
The required water for mortar, for 1 m³ of mortar, approximately 85.71 litres of water are needed, For 0.036 m³ of mortar: Amount of water 0.036 m³ x 85.71litres = 2.4098 litres.
Total cost of materials used per square metre:
Cement- 0.324 bags x 7,700.00= ₦2,494.00
Sand- 0.05184 tonnes x 8,000.00 = ₦414.72
Total cost of materials = ₦2,908.72
For the service required:
A skilled mason will charge ₦5,000.00 per day, while a semi-skilled mason is paid ₦3,500.00 per day. The total cost of labour is ₦8,500.00 per day. The labour cost per cubic metre (assuming 25 m² per day): ₦8,500 / 25 m² = ₦340.00 per square metre.
Total cost of materials used per square metre:
Cement- 0.324 bags x 7,700.00= ₦2,494.00
Sand- 0.05184 tonnes x 8,000.00 = ₦414.72
Total cost of materials = ₦2,908.72
Total cost:
The cost of laying cement sand screeded bed for floor finish per square metre is includes the cost of materials, labour, and equipment. Total Cost is the addition of ₦2,908.72 (Material costs) and ₦340.00 (Service cost) which gives a total of ₦3,248.72.
Schedule for Cement Sand Screeded Bed for Floor Finish:
Assumed quantities: 1 square metre
Total material square metre: ₦60,000.00.
Service or labour square metre: ₦1,700.00
Built up rate square metre: ₦61,700.00
3.6.2 Fix Tiles on Pool Wall and Pool Base Slab
Fixing wall tiles on the internal pool wall surface refers to the process of applying decorative and protective tiles to the interior walls of a swimming pool. This step is part of the "wall finishes, floor finishes" category under substructure work. It includes preparing the wall surface, ensuring proper alignment, applying adhesive, and securely attaching tiles. The tiles provide aesthetic appeal, enhance durability, and protect the pool’s structural integrity against water and chemical exposure.
Assumptions:
The task involves fixing floor tile on screeded floor finish
The tile size is 0.6 mx 0.6m, with 3 pieces per pack.
There is a 5% wastage on the tile used purchase
Water cement ratio: The water-cement ratio is 0.5
The bedding thickness of 36 mm
Calculations:
Materials used for floor tiles:
A. Tiles: The floor tiles used are the 0.6 metres long and 0.6 metres wide, each tile covers an area of 0.36 square metres. The package of tile contains 3 tiles. The total area covered by one package is 3 tiles x 0.36 square metres per tile = 1.08 square metres. To account for waste, let's add 5% to the total area covered by one package. 5% of 1.08 square metres is 0.054 square metres. The total area covered by one package, including waste, is 1.08 + 0.054 = 1.134 square metres. If we want to know how many packages, we need for 1 square metre of area, we divide 1 by the area covered by one package (1.134 square metres). This gives us approximately 0.88 packages per square metre.
B. Adhesive: The adhesive cement or bond is applied in a layer that's 0.006m thick. The volume of adhesive applied per square metre is 0.0006 cubic metres per square metre. The density of the adhesive material is 1600 kilograms per cubic metre. To find out how much the adhesive weighs per square metre, we multiply the volume per square metre (0.006 m³/m²) by the material density (1600 kg/m³), which gives us 9.60 kg per square metre. We need to account for waste, so we add 5% to the total weight per square metre. 5% of 9.60 kilograms is 0.48 kilograms. The total weight per square metre, including 5% waste, is 9.60 + 0.48 = 10.08 kilograms. Each bag of adhesive weighs 20 kilograms. To figure out how many bags we need per square metre, we divide the weight of one bag (20 kg) by the total weight per square metre (10.08 kg). This gives us approximately 0.504 bags per square metre.
Total cost of materials used per square metre:
Tile- 0.88 per x 13,000.00= ₦11,440.00
Adhesive- 0.05184 bag x 8,000.00 = ₦414.72
Total cost of materials = ₦11,852.72
For the service required:
A skilled tiler, a semi-skilled tiler and a tile cutter charges ₦800.00/square metre.
Total cost:
The cost of fixing floor tile cement sand screeded bed for per square metre is includes the cost of materials and labour. Total Cost is the addition of ₦11,852.72 (Material costs) and ₦800.00 (Service cost) which gives a total of ₦12,852.72
Schedule for Fix Tile on Pool Wall and Pool Base Slab:
Assumed quantities: 1 square metre
Total material square metre: ₦11,852.72
Service or labour square metre: ₦800.00
Built up rate square metre: ₦12,700.00
3.7. Waterproofing
Waterproofing in swimming pool construction, particularly for the substructure, involves applying specialized coatings or membranes to prevent water seepage and leaks. This ensures that the pool’s base and walls remain dry and structurally sound. The process typically includes sealing the concrete, brick, or block surfaces with materials like cementitious coatings or liquid rubber, creating a barrier that resists water infiltration. Waterproofing protects the pool's integrity, extending its lifespan and reducing maintenance needs.
3.7.1. Apply Liquid Tanking to Pool Base Slab
Applying liquid tanking or damp proofing to a pool base slab involves coating the slab with a waterproof membrane to prevent water ingress. This ensures the pool remains watertight and protects the structure from moisture damage. The process includes cleaning the slab, applying a primer if required, and evenly spreading or spraying the liquid membrane. Once cured, it forms a seamless barrier, critical for long-term durability in the pool’s substructure and effective water containment.
Assumptions:
The task involves applying cementitious materials and acrylic materials as waterproofing on Pool base slab
The task involves apply 2 coats of Masterseal 588 and 2 coats of Masterguard 300 or equal approved acrylic waterproofing coating.
The coverage area of the materials
Calculations:
To waterproof the surface of the swimming pool, two coats of waterproofing material will be applied.
Cementitious waterproofing:
This consists of a 10-litre liquid solution and a 25kg powder bag.
When mixed together, this combination covers 14 square metres when applied in two coats.
The cost of the Masterseal 588 cementitious waterproofing is ₦80,000 per set.
To determine the cost per square metre, we divide ₦80,000 by 14 square metres, which gives ₦5,714.28 per square metre.
Acrylic waterproofing:
A 20-litre bucket of acrylic waterproofing covers 30 square metres with two coats.
The cost of Masterguard 300 acrylic waterproofing is ₦120,000 per bucket.
The cost per square metre is calculated by dividing ₦120,000 by 30 square metres, resulting in ₦4,000 per square metre.
For the service required:
For cementitious waterproofing:
A team of two skilled workmen can apply 50 square metres per day.
The labour cost for applying the cementitious waterproofing is ₦3,000 per square metre.
For acrylic waterproofing:
A team of two skilled workmen can apply 30 square metres per day.
The labour cost for applying the acrylic waterproofing is ₦3,000 per square metre.
Total cost:
The cost of applying liquid tanking to pool base slab per square metre includes the cost of materials and labour. Total Cost is the addition of ₦5,714.28, ₦4,000 (Material costs) and ₦3,000, ₦3,000(Service cost) which gives a total of ₦15,714.28.
Schedule for Apply Liquid Tanking to Pool Base Slab:
Assumed quantities: 1 square metre
Total material square metre: ₦9,714.28
Service or labour square metre: ₦6,000.00
Built up rate square metre: ₦15,714.28