How It Works

Building coverage calculates how much of your plot you can actually build on after accounting for mandatory setbacks. Nigerian building regulations require minimum distances between your structure and property boundaries. The formulas are straightforward:

Lagos typically requires 6 meters front, 3 meters back, and 3 meters on each side. On a standard 50×100 ft plot (15.24m × 30.48m), that leaves you roughly 9.24m × 21.48m of buildable space, or about 198 square meters. That’s only 43% of your total 465 square meter plot.

The lost area goes to access, drainage, ventilation, and fire safety. You can’t build on it, but it’s still part of your property. Understanding this upfront prevents nasty surprises when you start construction and realize your house design won’t fit.

Standard Setback Requirements by Location

Here’s what different Nigerian cities typically require. These are minimums from building authorities, though your specific plot might have additional restrictions from estate covenants or local government.

Why Setbacks Exist

Setbacks serve multiple purposes. Front setbacks create space for drainage and prevent buildings from encroaching on roads. Side setbacks allow air circulation between structures and provide fire breaks. Back setbacks ensure every property has outdoor space and prevents one building from blocking another’s light and ventilation.

These aren’t arbitrary rules. Buildings too close together create health hazards (poor ventilation, mosquito breeding in stagnant water), fire risks (flames spread between structures), and access problems (emergency vehicles can’t reach properties). Violating setback requirements can get your building demolished, no matter how much you’ve already spent.

What Happens If My Coverage Is Too Low?

Coverage under 40% on residential plots means you’re losing more than half your land to setbacks. This happens on small plots (like half plots) or plots in low-density areas with large setback requirements. You have three options: build multiple floors, redesign to maximize the buildable footprint, or accept that you’re paying for land you can’t build on.

Building upward is often the solution. If you’ve got 200 square meters buildable on the ground floor but need 400 square meters total, build two floors. Just verify that your plot’s zoning allows multi-story construction and that the soil can support it.

Can I Get Setback Waivers?

Rarely, and it depends on your local building authority. Some areas allow reduced side setbacks if you’re building a boundary wall between properties or if your neighbor agrees in writing. Front and back setbacks are usually non-negotiable because they affect public infrastructure and drainage.

Don’t start construction hoping for a waiver later. Get written approval from the relevant authority before laying foundations. Unapproved structures can be demolished, and you’ll lose everything you’ve invested. The minor gain in buildable space isn’t worth the risk.

Do Corner Plots Have Different Rules?

Sometimes. Corner plots border two streets, which might mean double front setbacks (one for each road). This reduces your buildable area significantly compared to interior plots of the same size. However, some authorities give relief by treating one side as a regular side setback instead of a full front setback.

Check with your local building authority before buying a corner plot. The extra road frontage seems attractive, but if you’re required to maintain full front setbacks on both sides, you might end up with 20-30% less buildable space than an interior plot.

How Do Setbacks Affect Construction Costs?

Lower coverage means more cost per usable square meter. If you’re building 300 square meters on a plot with 40% coverage, you needed a 750 square meter plot. At ₦5 million per plot, that’s roughly ₦16,667 per built square meter just for land. Better coverage (say 50%) means you’d only need a 600 square meter plot, reducing land cost per built meter.

This matters when choosing between plots. A cheaper plot with terrible coverage might end up costing more per usable space than a slightly more expensive plot with better coverage. Run the numbers before deciding.

What About Balconies and Canopies?

Typically, these can’t extend beyond setback lines. A balcony jutting 2 meters into the front setback violates the rule just as much as extending the main building. Some jurisdictions allow minor projections (like roof overhangs under 1 meter), but substantial structures like covered patios or extended balconies usually count as part of the building footprint.

Plan your design within the buildable area from the start. Trying to maximize space by extending into setbacks will cause problems during building approval or inspection. Design what fits legally, not what you wish you could build.

Should I Buy a Bigger Plot to Get More Buildable Area?

Not always. Setbacks are fixed distances, not percentages. Whether your plot is 300 square meters or 1,000 square meters, you still lose the same amount to setbacks (about 6m front, 3m back, 3m each side). This means larger plots have better coverage percentages.

A 50×100 ft plot loses about 267 square meters to setbacks (57% of the plot). A 100×200 ft plot loses the same 267 square meters but that’s only 29% of the total. Larger plots are more efficient in terms of usable space per naira spent, assuming setbacks stay constant.

What If I Measure My Plot and It’s Smaller Than Expected?

Get a professional survey immediately. If your actual plot is 48×98 ft instead of the advertised 50×100 ft, your buildable area shrinks proportionally. Those missing 2-4 feet might not sound like much, but they reduce your already limited buildable space further.

Don’t start construction based on advertised dimensions. Use the surveyed dimensions to calculate actual buildable area. Better to discover problems now than after you’ve poured your foundation and realize nothing fits.

Can I Use Setback Areas for Anything?

Yes, but not structures. You can landscape, plant gardens, install walkways, or put in driveways. Some people build pergolas or gazebos in setback areas, but these are technically violations if they’re permanent structures. Moveable features (like garden furniture) are usually fine.

Setback areas also handle drainage. Water from your roof and yard flows through these spaces to the street or designated drainage channels. Don’t block or cover setbacks entirely with concrete, you’ll create flooding problems for yourself and neighbors.

How Accurate Does My Calculation Need to Be?

Very. If you’re designing a building, work with exact surveyed dimensions and official setback requirements. A 10cm error might seem minor, but it compounds when you’re already working with tight margins. Architects and builders need precise measurements, not rough estimates.

Use this calculator for planning and comparison, but get professional drawings based on actual survey data before starting construction. The calculator gives you a realistic expectation of what’s possible, your architect makes it work within exact legal constraints.