If you have been dreaming of a 5-bedroom duplex in Lagos, you have probably already started doing the maths in your head. You have asked a few people, seen some figures thrown around online, and maybe started quietly setting money aside. The problem is that the numbers you find rarely match each other and almost none of them match what you will actually spend when work begins.
This article will not sugar-coat it. Building a 5-bedroom duplex in Lagos in 2026 is a serious financial undertaking. But if you go in with honest numbers, a clear breakdown, and an understanding of what drives costs up or down, you can plan a build that actually gets finished.
The Headline Number
A 5-bedroom duplex in Lagos today will cost you between ₦100 million and ₦200 million for construction alone and that figure does not include the cost of land.
The wide range is not vague. It reflects a real fork in the road that every builder faces: are you building a standard, solid, well-finished home or are you going luxury? A standard build sits between ₦100 million and ₦120 million. A premium or luxury finish pushes you to ₦150 million and well beyond ₦200 million depending on your choices.
The cost per square metre in Lagos for a duplex of this type currently runs between ₦90,000 and ₦130,000. The larger your footprint, the more every decision about materials and finishes multiplies.
Why a Duplex Costs More Than a Bungalow
Before the breakdown, it helps to understand why a duplex is fundamentally more expensive to build than a bungalow of similar bedroom count, beyond just the extra floor.
A duplex requires a suspended concrete slab to carry the upper floor. That slab, the decking is one of the most material and labour-intensive elements in the entire build. It requires large volumes of reinforced concrete, significant amounts of iron rods, formwork to support the pour, and skilled labour to execute correctly. A mistake at decking level is not just expensive to fix, it is dangerous.
The structural demands of a two-storey building are also higher than a bungalow, meaning your foundation, columns, and beams must be engineered to carry greater loads. This is why cutting corners on your structural engineer is particularly costly on a duplex, the consequences are not cosmetic, they are structural.
Stage-by-Stage Cost Breakdown
Architectural Plans, Design Fees, and Building Permits
Your architectural and design fees for a 5-bedroom duplex will run between ₦2,000,000 depending on the complexity of the design and the firm you engage. On top of that, building permit approval from LASPPPA or LASBCA adds between ₦150,000 and ₦3,000,000 depending on the size of your project and the location. Larger, more prominent sites in certain LGAs attract higher permit fees.
Do not treat this as an optional cost. An unapproved duplex is a liability not an asset.
Foundation and Substructure
The foundation range for a duplex is wide and location-dependent. On firm ground in areas like Ikorodu, Ojodu, or parts of the mainland, a well-engineered strip or pad foundation will sit at the lower end around ₦7 million to ₦10 million. But build on Lagos Island, Lekki, Ajah, or any waterlogged terrain, and you are looking at raft or pile foundation requirements that can push this figure to ₦20 million to ₦25 million.
This is why your soil test which costs between ₦300,000 upwards is not optional. It tells your structural engineer exactly what kind of foundation your ground demands. Skipping it and guessing wrong is a multi-million naira mistake.
Superstructure: Blockwork, Columns, and Decking
This covers all blockwork from DPC level up to lintel level on both floors, the reinforced concrete columns and beams, and critically, the suspended concrete slab (decking) between the ground and first floor. The decking alone is a significant portion of this budget. Current prices for key materials driving this stage: cement is selling between ₦10,000 and ₦15,000 per 50kg bag, iron rods are running between ₦850,000 and ₦1,400,000 per tonne, and 9-inch blocks are going for ₦700 to ₦800 per unit. A 5-bedroom duplex will consume thousands of blocks and significant tonnage of iron rods across both floors.
Roofing
Roofing cost is driven by the span of the building, the complexity of the roof design, and your choice of roofing material. Long-span aluminium sits at the lower end of the cost range. Stone-coated steel tiles are more expensive upfront but offer significantly better durability and aesthetics, important for a duplex where curb appeal matters. Hip roofs, which are common on duplexes, use more material than simple gable designs and cost accordingly.
Finishing Works: This is the stage that separates a house from a home and it is where the standard versus luxury split becomes most visible. Finishing covers plumbing and electrical completion, tiling, plastering, POP ceilings, painting, doors, windows, and all fittings.
Breaking it down further: tiling alone runs between ₦2,000,000 and ₦5,000,000 depending on tile quality and the size of the floor area. POP ceiling installation adds ₦1,000,000 to ₦2,500,000. Internal and external painting runs between ₦1,000,000 and ₦4,000,000. Plumbing and electrical combined easily add another ₦5,000,000 to ₦10,000,000 for a duplex of this size.
The luxury end of finishing is essentially limitless, imported Italian tiles, smart home systems, feature walls, custom kitchens, and high-end bathroom suites can push your finishing budget alone past ₦40,000,000.
Labour: Labour for a two-storey, 5-bedroom duplex runs higher than a bungalow in both total cost and duration. Skilled masons, carpenters for formwork and roofing, tilers, electricians, plumbers, and general workers across a 12 to 18 month build add up considerably. The longer your project runs, particularly if funding pauses cause stoppages, the more your total labour cost climbs.
The Location Factor: Not All Lagos is the Same
Where your duplex sits within Lagos changes the cost equation significantly.
The mainland areas like Ojodu Berger, Egbeda, Ikorodu, Agege generally offer firmer ground, better material logistics, and lower Omo-Onile pressure. Construction costs here tend to sit closer to the lower end of the ranges above.
The island and its fringes, Lekki, Ajah, Victoria Island, Ikoyi, Lagos Island proper bring waterlogged terrain, expensive foundation requirements, higher logistics costs for material delivery, and premium community levies. The same duplex that costs ₦110 million to build in Ojodu could cost ₦160 million or more in Lekki Phase 2.
This does not make island building a bad decision: land values and rental yields on the island justify the higher construction cost for many investors. But go in knowing the full picture.
Hidden and Easily Forgotten Costs
Beyond the build itself, budget for the following which contractors never include in their quotes:
Borehole and water system: ₦800,000 to ₦2,500,000. Septic tank: ₦500,000 to ₦1,500,000. Perimeter fencing and gate: ₦2,000,000 to ₦6,000,000. Omo-Onile and community levies: ₦200,000 to ₦1,000,000 or more. Site security for the duration of construction: ₦500,000 to ₦1,200,000. Generator and fuel: ₦300,000 to ₦600,000. Contingency fund: a minimum of 15% to 20% of your total construction budget, set aside and untouched until genuinely needed.
So What Should You Actually Budget?
For a 5-bedroom duplex in Lagos in 2026, a realistic all-in budget looks like this:
- For a standard build on firm ground on the mainland budget ₦100 million to ₦150 million including professional fees, permits, infrastructure, and contingency.
- For a standard build on island or waterlogged terrain budget ₦150 million to ₦200 million.
- For a premium or luxury finish anywhere in Lagos start at ₦200 million and plan for more.
These are not contractor quotes. They are honest planning figures for a homeowner who wants to finish what they start.
One Final Word
The duplex dream is achievable. Thousands of families in Lagos complete them every year. The ones that finish are not always the ones with the biggest budgets, they are the ones who knew the real numbers before they started, planned for the unexpected, and worked with professionals who kept the project honest from foundation to rooftop.
If you want a detailed Bill of Quantities for your 5-bedroom duplex, priced to your specific land, location, and finish level.
Our team at Bullionrise Consult can prepare one before you spend a naira on materials. That single document could save you millions. Reach out today.
