Cost of Building a 4 Bedroom Duplex in Nigeria

Cost of Building a 4 Bedroom Duplex in Nigeria

Before you start to dig the earth, make sure you have all therequired APPROVED 

documents for the construction process:

• Architectural drawings.
• Structural drawings.
• Mechanical drawings.
• Electrical drawings.

Some people go-ahead to break earth without some of these drawings and hope everything turns out fine.

That is a wrong mentality. Please follow the right process. It helps you plan all the way.

In calculating the cost of building a duplex in Nigeria, it is advisable to breakdown the construction process into stages.

This is the norm and is actually helpful in planning your progress. For a duplex, the construction stages can be split into the following:

• Foundation / Soak-away Stage.
• DPC to lintel level/ground floor Stage.
• First floor/decking stage.
• Staircase Stage.
• First-floor lintel stage.
• Roofing Stage.
• Plastering / Finishing Stage.

Cost of Foundation / Soak-away Stage

This is the first stage of construction and it includes setting out, digging, concrete work, block laying, backfilling and flooring as the processes in this stage.

Furthermore, the cost of this stage differs with respect to the soil condition.

Material Requirements for Setting-out with profiles

• 4 pieces of 1 x 12 plank @ NGN 1,200 each plus NGN 800 (for dividing each into 5 (@ NGN 200 each) = NGN 5,600
• 4 bundles of Pegs @ NGN 1,200 each = NGN 4,800
• 2″ and 3″ Nails = NGN 1,200 worth of nails
• 4 bundles of rope @ NGN 200 each = NGN 800
• Labour = NGN 5,000

Estimated cost of setting-out = NGN 17,400.

Material Requirements for Digging / Excavation

• Some diggers and shovels will be needed for the job. These tools can cost about NGN 2,000 to rent.
• Labour = NGN 10,000

Estimated cost of digging = NGN 12,000.

Material Requirements for Concrete Columns

The duplex design affects the cost of this section as this cost is determined by the number of columns in the design.

The structural drawing plays a key role in this section, as it indicates the number and design clearly.

For the basis of this calculation, we have earlier said we are using a 4 bedroom duplex. Hence, the number of columns in this design amounts to twenty-two (22) nos.

The standard column dimension is 350mm by 350mm by 3000mm (height).

For constructing one column (standard mix ratio 1: 3: 6 comprising cement, sand, aggregate), you need the following materials below for 22 nos concrete column:

• 35 bags of cement @ NGN 2,600 each = NGN 91,000
• 5 tonnes of sand = NGN 10,750
• 20 tonnes of granite = NGN 100,000
• 1 tonne 12mm steel Reinforcements = NGN 170,000
• Some diggers, pans, and shovels will be needed for the job. These tools can cost about NGN 5,000 to rent.
• Labour = NGN 30,000

Estimated cost of concrete columns = NGN 406,750.

Material Requirements for Concrete work / Blinding

For a standard foundation of 150 mm base-thickness, assuming 0.45 m (breadth or height) and 85.5 m (entire length) = 5.77125 m3

• 10 bags of cement @ NGN 2,600 each = NGN 26,000
• 20 tonnes of sand x 2 = NGN 80,000
• 20 tonnes of Granite = NGN 100,000
• We don’t need reinforcements (Iron bars) because the soil is good, firm and dry.
• Liters of water as needed.
• Labour = NGN 25,000

Estimated cost of concrete work = NGN 231,000.

Material Requirements for Laying Foundation Blocks

Using 9-inch blocks and laying 4 coaches, you will need

• 12 bags of cement @ NGN 2,600 each = NGN 31,200
• 644 pieces of 9-inch vibrated blocks (including 10 percent wastage) @ NGN 170 each = NGN 109,480
• Plumbing work = NGN 25,000
• The remaining sand from concrete work will be used here.
• Labour = NGN 35,000

Estimated cost of laying foundation blocks = NGN 200,680.

Material Requirements for Filling

I suggest digging the soak-away and septic tank alongside making the foundation so that the soil dug-up from the soak-away pit, septic tank and well can be used for filling the foundation.

This will save you the cost of buying some trips of sand for foundation filling, and also save you the cost of clearing the dug-up soil in a case where it is not used for filling.

After filling the foundation, water it for about 10 hours and leave it for days (or some weeks) before flooring for natural compaction. 

In the end, you might need to buy just a few trips of sand if the soil dug-up from the well and septic tank is not enough.

Assuming you buy:

• 3 trips of 20 tonnes laterite (fairly clayey) at NGN 18,000 = NGN 54,000
• Labour = NGN 10,000

Estimated cost of filling foundation = NGN 64,000

Material Requirements for Foundation Casting / Flooring

• 25 bags of cement @ NGN 2,600 = NGN 65,000
• Waterproof / nylon = NGN 15,000
• Remaining granite and sand from concrete work will be used here.
• Labour = NGN 18,000

Estimated cost of flooring = NGN 98,000

Material Requirements for Septic Tank, Soak-away pit and Well

The septic tank, soak-away pit, and well should be constructed first in order to have water for the work and sand for filling the foundation later.

• 700 pieces of 6-inch vibrated blocks @ NGN 150 / block (for a septic tank of 3m x 3m x 3m) = NGN 105,000.
• 22 bags of cement @ NGN 2,600 = NGN 57,200 (including plastering).
• Number of well-rings as required.
• Sand and granite from concrete work will be used here.
• Labor for septic tank, soak-away pit and well = NGN 80,000

Estimated cost of constructing both the septic tank, soak-away and well = NGN 242,200.

Total Estimated Cost for this stage = NGN 1,272,030 (excluding the cost of well rings).

Cost of Construction From Damp Proof Course (D.P.C) To Lintel Level

This is the next stage in the construction process and begins where the German floor ends. 

It covers the main block work including wall partitions for the various spaces in the house. The materials listed below are just estimates of what you get in a modest 3-bedroom flat.

Again, ensure you get a Bill of Quantities for your building plan as that’s the only way to know the exact material requirements for your house. This stage ends at the roof level.

Material Requirements and Labour for Block work

• 2100pcs of 6-inch stone dust vibrated blocks @ NGN 150 = NGN 315,000.
• (The cost increases when you use 9-inch blocks)
• 15 tonnes of sharp sand = NGN 40,000
• 30 bags of cement @ NGN 2,600 = NGN 78,000
• Labour = NGN 120,000

Estimated cost of block work = NGN 553,000. (This includes the two coaches of blocks after lintel)

Material Requirement for Lintel Casting

• 20 length of 12mm rod @ NGN 2,100 / length = NGN 42,000
• 10 length of stirrups @ NGN 500 / length = NGN 5,000
• 35 length of 1 x 12 x 18 wood @ NGN 1,700 / length = NGN 59,500
• Nails plus wire for binding = NGN 13,000
• 8 bags of cement @ NGN 2,600 = NGN 20,800
• Remaining sand will be used here.
• Remaining granite from concrete work is used.
• Labour plus carpenter = NGN 30,000

Estimated cost of the lintel level = NGN 170,300

Estimated Total Cost for this stage = NGN 723,300.

Cost of First Floor Decking Stage

For this stage, we would require the total floor area in cubic meters since there is a depth to it. The floor is 6 inches (150mm) thick.

The total cubic meter for the used floor plan is 39.6 cubic meters. Hence, the cost of the reinforced concrete floor slab with ratio 1:2:4 is as follows:

Here you would need the following:

• Bamboo
• Cement
• Sand
• Granite
• Reinforcements
• wood

It is a long process of calculating so I have broken this down to arrive at the cost below.

NGN 25,000 per cubic meter for 39.6 cubic meters = NGN 990,000.

Estimated Total Cost for this stage = NGN 990,000.

Cost of Staircase Stage

For this stage, we would require the total floor area in cubic meters since there is a depth to it. The floor is 6 inches (150mm) thick.

The total cubic meter for the staircase is 3 cubic meters. Hence, the cost of the reinforced concrete floor slab with ratio 1:2:4 is as follows:

Here you would need the following:

• Cement
• Sand
• Granite
• Reinforcements
• wood

It is a long process of calculating so I have broken this down to arrive at the cost below.

NGN 25,000 per cubic meter for 3 cubic meters = NGN 75,000.

Estimated Total Cost for this stage = NGN 75,000.

Cost of Construction From First Floor To Lintel Level

This stage covers the main block work including wall partitions for the various spaces in the house.

The materials listed below are just estimates of what you get in a modest 4-bedroom bungalow. Again, ensure you get a Bill of Quantities for your building plan as that’s the only way to know the exact material requirements for your house. This stage ends at the roof level.

Material Requirements and Labour for Block work

• 2100pcs of 6-inch stone dust vibrated blocks @ NGN 150 = NGN 315,000.
• (The cost increases when you use 9-inch blocks)
• 15 tonnes of sharp sand = NGN 40,000
• 30 bags of cement @ NGN 2,600 = NGN 78,000
• Labour = NGN 120,000

Estimated cost of block work = NGN 553,000. (This includes the two coaches of blocks after lintel)

Material Requirement for Lintel Casting

• 20 length of 12mm rod @ NGN 2,100 / length = NGN 42,000
• 10 length of stirrups @ NGN 500 / length = NGN 5,000
• 35 length of 1 x 12 x 18 wood @ NGN 1,700 / length = NGN 59,500
• Nails plus wire for binding = NGN 13,000
• 8 bags of cement @ NGN 2,600 = NGN 20,800
• Remaining sand will be used here.
• Remaining granite from concrete work is used.
• Labour plus carpenter = NGN 30,000

Estimated cost of the lintel level = NGN 170,300

Estimated Total Cost for this stage = NGN 723,300.

Cost of Roofing Duplex Stage

The cost of roofing varies greatly with the type of roofing materials and design you choose to use. The cost given below represents 0.45 mm thick aluminum roofing sheets. The true cost of all stages still remains that shown on the bill of quantity document.

Material Requirements for Roofing

• 320 length of 2 x 3 x 12 wood @ NGN 450 = NGN 144,000
• 45 length of 2 x 6 x 12 @ NGN 840 = NGN 38,250
• 25 length of 1 x 12 x 12 wood @ NGN 1,400 = NGN 35,000
• 1/2 bag of 2-inch nails @ NGN 5,800 = NGN 2,900
• 11/2 bags of 3-inch nails @ NGN 6,000 = NGN 9,000
• 1/2 bag of 4-inch nails @ NGN 6,500 = NGN 3,250
• Aluminium (0.45mm thick) roofing, transportation and Labour = NGN 685,900

Total Estimated Cost for the roofing stage = NGN 918,300.

Cost of Finishing Stage

This stage includes plastering, wiring, plumbing, fixing of windows, doors, tiles, and other essentials.

The cost here varies with respect to the quality of materials you use. Below is an estimate for a very modest finishing.

Material Requirements for Electrical works

• Wires, Pipes, Conduit Boxes, etc = NGN 400,000
• Material Requirements for Mechanical and Plumbing Works
• Kitchen sink, Pipes, WC, Washing Hand Basin, Overhead Tank, Shower, etc = NGN 500,000

Material Requirements for Ceiling

• Woods for nogging, P.O.P Sheets, External wood finishing, P.V.C Boards, Tank nails, etc plus labor = NGN 450,000

Material Requirements for Windows and Doors

• Windows, doors, burglary proof, and fixtures plus labor = NGN 1,500,000

Material Requirements for Wall Rendering and Painting

• Plastering and painting plus labor = NGN 1,500,000

Material Requirements for Floor Finishes

• Tiles and others plus labor = NGN 1,000,000

Estimated Total Cost for this stage = NGN 5,350,000.

Grand Total = NGN 1,272,030 + NGN 723,300 + NGN 990,000 + NGN 75,000 + NGN 723,300 + NGN 918,300 + NGN 4,350,000

= NGN 10,051,930

As you can see from the calculations, we arrived at a total cost of building a 4 bedroom duplex which is a little above NGN 10,051,930.

This involves just the construction of the 4 bedroom duplex in Nigeria.

The design is a very simple one with an aesthetically conscious approach. For more complicated designs, the cost could exceed what we have calculated above.

As for the furniture fittings, you have a variety of options you can choose from. 

If you make plans, the cost of building a duplex in Nigeria would be reduced to the barest minimum. All it takes is for you to follow the procedures laid out above.

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