How Long Does It Take to Build a Duplex in Lagos?

TL;DR: A standard 4-bedroom duplex in Lagos takes 12 to 18 months from breaking ground to moving in, assuming steady funding and no major design changes. Foundation and approvals add 2 to 4 months before you even see blockwork, and rainy season, material shortages or late payments can stretch the project to 24 months.

People ask me this every week, usually after they have bought land in Ajah or on the mainland and want to be in by Christmas. I give them the same answer: a duplex is not a 6-month job done properly. Here is how the time actually breaks down on a typical Lagos site.

Before you touch the ground: design and approvals (2–4 months)

Your clock starts before the first peg. You need architectural drawings, structural drawings, and mechanical/electrical drawings, all signed and sealed by registered professionals. In waterlogged areas like Lekki, Ajah and Sangotedo, add a soil test — a good engineer will not design your raft or pile foundation without it.

Then comes LASPPPA planning approval and LASBCA stage certification. The e-Planning Permit portal promises processing within 28 working days after screening, but that assumes your title (C of O or Governor's Consent), survey plan, tax clearance and drawings are clean on first submission. Queries mean revised drawings and resubmission. I tell clients to budget 6 to 12 weeks for approvals, and to use that time to price materials properly rather than rushing to site.

Do not start foundation work without your approval letter and LASBCA authorisation to commence. Starting early to "save time" is how people get a demolition notice and lose months instead.

Foundation to ground floor (6–10 weeks)

This is where Lagos soil decides your timeline. On firm ground in places like Alimosho, parts of Ikorodu or Agege, a strip foundation for a duplex can move quickly. In the Lekki-Ajah belt, you are usually on raft or piles because of the water table.

Setting out, excavation, blinding, column bases, raft beams, ground floor slab (German floor) and curing will take 4 to 6 weeks for the foundation alone in normal conditions. Add sandfilling and compaction if your plot is low. If you hit rain in June to September, add another 2 weeks for water pumping and curing delays. I have watched a Badore foundation sit flooded for 10 days because the estate drainage was blocked — no amount of shouting at the contractor changes that.

Carcass: blockwork, decking and roofing (4–6 months)

Once the slab is done, the building starts to read as a house, but this is the longest stretch. Ground floor blockwork to lintel, casting columns and lintels, formwork and reinforcement for the suspended floor, then casting the deck — each stage needs curing time. Concrete does not care about your deadline; strip formwork too early and you pay for it later.

Upper floor blockwork, roof beams, parapet if you want one, and roofing follow. Roofing choices matter: stone-coated tiles need careful carpentry and imported sheets, long-span aluminium is faster but noisier in rain. A realistic allowance is 4 to 6 months from ground floor slab to a roofed, weather-tight shell, assuming your roofer and carpenter are booked and materials are on site.

Stage inspections by LASBCA happen at foundation, lintel/DPC, decking and roofing. You must give seven days' notice before each stage. A failed inspection means corrective work and a re-inspection slot — another week or two gone.

Finishes: where duplexes actually take time (4–7 months)

Clients think the house is "almost done" at roofing level. It is about 55% done in money and time.

Plastering, first-fix electrical and plumbing, window and door installation, tiling, screeding, POP or PVC ceilings, kitchen and wardrobe joinery, sanitary ware, and painting run in overlapping sequences but cannot all happen at once. Good finishing trades in Lagos are booked weeks ahead. Your tiler finishes, then your electrician comes back for second fix, then painter touches up where they drilled. Rushing this stage is visible for years in uneven tiles and paint on sockets.

External works — fence, gate, interlocked compound, borehole, soakaway, septic tank, and drainage — are often left to the end and then delayed by rain. Budget a full month for outside alone.

What stretches a 12-month build to 24 months

In my experience supervising and inspecting builds from Ajah to Ikeja, delays are rarely technical. They are cash-flow and decisions.

Funding gaps are number one. A duplex consumes money in waves — decking and roofing are the two most expensive single stages. If you start with ₦10M and hope to find the next tranche as you go, the site will sit idle and your contractor will move his best workers elsewhere.

Number two is mid-project changes: moving a wall after plastering, changing window sizes after lintel casting, or upgrading finishes halfway through. Every change is a demolition plus a reorder.

Number three is the rainy season. Building from April to October means you will lose days to rain, flooded access roads, and late material deliveries. It is still possible to build through the rains, but your programme must allow for it.

Diaspora builders feel all three harder because approvals and decisions wait on time zones. That is why I advise anyone building from abroad to have a trusted clerk of works on site with photo reports, and to lock the design before the foundation is dug.

If you want a realistic programme, ask your builder for a stage-by-stage bar chart with curing times shown, not just "foundation 1 month, finishing 2 months." The honest ones will show you 13 to 16 months for a standard finish. Anyone promising a full 5-bedroom duplex in 4 months is either cutting corners on curing or planning to disappear after decking.

Frequently asked questions

Can a duplex be built in 6 months in Lagos?

Only in very unusual circumstances — a small, simple design, firm soil, all materials pre-purchased, and a large crew working in dry season. For a normal 4-bedroom duplex with proper curing and approvals, 6 months is not a safe plan and rushed concrete curing is a common cause of defects.

How long does approval take before building starts in Lagos?

Allow 6 to 12 weeks for LASPPPA planning approval and LASBCA commencement authorisation if your title and drawings are in order. The official target is 28 working days after screening, but queries and resubmissions regularly add time.

What takes the longest when building a duplex?

Finishes take the longest single block of time — tiling, joinery, electrical and plumbing second fix, and painting typically run 4 to 7 months combined. Decking and roofing are the most expensive stages, but finishing determines when you can actually move in.

Does rainy season stop building in Lagos?

Rain rarely stops a site completely, but it slows foundation work, external works and deliveries, and can flood low plots in Ajah and Lekki. Experienced builders programme around June to September and avoid starting foundations at the peak of the rains.

How can I keep my duplex build on schedule?

Fix your design before you start, keep a 10%–15% contingency for price movement, pay your contractor on certified milestones (not demands), and give LASBCA the required seven days' notice for stage inspections. Weekly photo and cost reports stop small delays becoming months.

Related reading

• How Much Does It Cost to Build a 4 Bedroom Duplex in Lagos? (2026)
• Building Approvals in Lagos: LASBCA Permits Step by Step
• Cost of Building vs Buying in Lagos: Which Wins in 2026?
• Building from Abroad: Monitoring Your Project Without Wahala