Cost of building a duplex in Nigeria (foundation to DPC)

The cost of building a duplex in Nigeria varies from location to location, and it is influenced by the size of the building, the price of construction materials, the design specifications, the expertise required, and the environment. Depending on the soil condition, raft foundation will be more expensive than pad foundation, while deep foundations such as piles will be more expensive than raft foundation.


The construction cost of a building can also be influenced by the nature of contract, and it will be in the best interest of the client to hire a professional representative, consultant, or project manager who will interface for him starting from the onset of the project.

Excavation of trench for construction of a duplex by the author

Intending home owners must engage professionals during the design stage, in order to get their project right from the scratch. The construction of the substructure of a building (foundation) is very critical, and has very little to do the with the specifications of the architect except in terms of arrangement and setting out. The major costs involved in the foundation of a building such as residential duplexes are functions of engineering design.

Setting out of column starter bars in a substructure

A good design will minimise cost, identify possible challenges in the construction of the building, guarantee the integrity and structural stability, and subsequently lead to less difficulties during construction. Now that you are here, it is important that you play your part as an intending home owner and patronise registered professionals in your projects. This can help stop the problem of building collapse in Nigeria.

In this article, let us briefly review the cost of constructing a simple duplex from the foundation to the DPC (ground floor slab). As stated earlier, the cost is dependent on the drawing provided by the structural engineer and not by guess work. The price of materials in the locality will also influence the cost. Therefore, the cost provided in this article is a guide and merely informative.

The plan of the building is shown below;


Foundation layout of a duplex

From the foundation layout, it can be seen that the structural engineer provided three types of pad foundations (BT1, BT2 and BT3). The size of any foundation is determined by the strength of the soil, and the load coming from the column. The details of the pad bases are given below;

Base Type 1 and Base Type 2 structural details
Base Type 3 structural details

The processes that will take place in the construction of the foundation are;

(1) Setting out works
(2) Excavation works
(3) Reinforcement works
(4) Formwork
(5) Concrete works
(6) Block work
(7) Back filling and compaction
(8) Casting of ground floor slab

(1) Setting out
Width of building = 12.275 m
Length of building = 15.7 m

If we make a setback of 1.2 m from all sides of the building line for the profile board, the total perimeter of the profile board will be 65.55 m. At 1.5m spacing, we will need 45 pegs, and 20 pieces of 2″ x 3″ softwood. Let us assume that the equipment needed for setting out are available except lines.

(a) 2” x 3” soft wood – 20 pcs @ ₦400 = ₦8,000
(b) 2” x 2” pegs – (3 bundles @ 20 pieces per bundle) @ ₦1000 = ₦3,000
(c) Nails – 1 bag of 2 inches nail, and 1 bag of 3 inches nail = ₦10,000
(d) 6 rolls of lines = ₦2,000

Labour and supervision cost (say) = ₦30,000

Total cost of setting out = ₦53,000


(2) Excavation works
(a) Excavation of 19 column bases according to structural drawings to a depth not less than 1200 mm to receive blinding for pad foundation – Total volume = 42.42 m3
19 column bases @ ₦1000 = ₦19,000

(b) Excavation of strip footing 690 mm wide and 950 mm deep to receive mass concrete strip footing – Total volume = 70.13 m3
Labour cost for 30 partitions @ ₦1000 = ₦30,000
Supervision cost = ₦20,000

Sub-total for excavation = ₦69,000

Excavation and column setting out works

(3) Concrete works
(a) Provision of 50 mm thick weak concrete blinding (1:3:6) on column bases to receive footing reinforcement – Total volume = 1.8 m3
Cement – 8 bags @ ₦2,600 per bag = ₦20,800
Sand – 1.98 tonnes @ ₦2000 per tonne = ₦3,960
Granite – 2.52 tonnes @ ₦7750 per tonne = ₦19,530

(b) Provision of concrete with strength not less than 25 MPa after 28 days for the column bases – Total volume = 10.7 m3
Cement – 65 bags @ ₦2,600 per bag = ₦169,000
Sand – 12 tonnes @ ₦2000 per tonne = ₦24,000
Granite – 15 tonnes @ ₦7750 per tonne = ₦116,250

(c) Provision of concrete with strength not less than 20 MPa after 28 days for the mass concrete strip footing – Total volume = 8.5 m3
Cement – 51 bags @ ₦2,600 per bag = ₦132,600
Sand – 9.35 tonnes @ ₦2000 per tonne = ₦18,700
Granite – 12 tonnes @ ₦7750 per tonne = ₦93,000

Labour cost for mixing, pouring and consolidation of concrete = ₦125,000
Supervision cost = ₦50,000

Cost of concrete works = ₦597,570

(4) Reinforcement Works
(a) Column base mat reinforcement
50 lengths of Y12 mm @ ₦2,800 per length = ₦140,000

(b) Column starter bars
20 lengths of Y16 mm @ ₦3,500 per length = ₦70,000

(c) Column links
13 lengths of Y8mm @ ₦1,100 per length = ₦14,300

(d) Binding wire
1 roll of binding wire @ ₦4,500 per roll = ₦4,500

Labour cost for cutting, bending, and placement of reinforcement = ₦40,000

Cost of reinforcement works = ₦268,800

(5) Blockwork
(a) Total number of 9 inches blocks required to raise the building to DPC = 1600 blocks
1600 pieces of 9” blocks @ ₦200 per block = ₦320,000

Labour cost for laying of blocks = ₦77,500
Supervision = ₦20,000

Cost of blockwork = ₦417,500

Blockwork in substructure

(6) Formwork
(a) Provide formwork for sides of columns up to a height not less than 1225 mm.
20 pieces of 1” x 12” x 12 plank @ ₦1,200 per plank = ₦24,000

Labour cost for formwork preparation and placement = ₦15,000

Cost of formwork = ₦39,000

(7) Backfilling and compaction
(a) Backfill and compact substructure to a height not less than 550 mm above ground level with selected backfill material. Total volume = 100 m3
33 trips (165 tonnes) of laterite @ ₦12,000 per trip = ₦396,000
Labour cost for filling and compaction = ₦50,000

Total Cost of filling and compaction = ₦446,000

(8) Damp proof membrane
(a) Provide and install damp-proof membrane over an area not less than 181 m2
181 m2 of high density polythene sheet @ ₦385 per m2 = ₦69,685

Damp proof membrane = ₦69,685

(9) BRC mesh
(a) Provide and Install A142 BRC MESH (TOP) over an area not less than 181 m2
181 m2 of A142 BRC Mesh @ ₦1,200 per m2 = ₦217,200

Labour cost for installation = ₦5,000

Total Cost of BRC mesh = ₦222,200

(10) Ground floor Slab
(a) Cast ground floor slab over an area not less than 181 m2 and concrete of volume = 27.15 m3
Cement – 163 bags @ ₦2,600 per bag = ₦423,800
Sand – 30 tonnes @ ₦2000 per tonne = ₦60,000
Granite – 40 tonnes @ ₦7750 per tonne = ₦310,000

Labour cost for mixing, pouring and consolidation of concrete = ₦170,000
Supervision cost = ₦50,000
Casting of ground floor slab = ₦1,013,800

Therefore, the tentative cost of raising the building from foundation to DPC is ₦3,196,555 without the contractor’s profit and overhead.

Through design review and cost control, this price can be considerably reduced.

Completed substructure of a duplex by the author

For design, construction, and professional management of your building project, contact;

Structville Integrated Services Limited
E-mail: info@structville.com
Phone call: +2348060307054
Whatsapp: +2347053638996

4 COMMENTS

  1. My commercial abilities for building structures have improved reading this article.

    Nigeria prospective clients who want to build their homes must know the value the Engineer brings to the table for their home project which are budget management and cost control.

    This will save the client lot of money

  2. I have just updated my quantity surveying knowledge via reading this post. Thanks for the knowledge you’re continuously imparting.

  3. Knowledge is power, so…!, I have been working for my client for pie nut, now I understand and now my what.

    Engr. Obani
    Wisdom will not kill you oo
    Thank you sir, for all this great Articles == More Grace.

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