How to Prepare a Bill of Quantities in Nigeria — Step-by-Step Guide (2026)

Why Preparing a Bill of Quantities Is the Most Important Step in Any Nigerian Building Project

Most Nigerian self-builders skip the Bill of Quantities and go straight to hiring a contractor — usually getting a lump-sum quote that is either wildly inflated or so underpriced that the contractor abandons the site halfway through. A properly prepared BoQ gives you a complete, itemised cost breakdown before any work starts, puts you in control of material procurement, and creates a document you can tender to multiple contractors for fair, comparable pricing.

Whether you prepare it yourself for a smaller project or hire a Quantity Surveyor for a larger one, understanding how a BoQ is put together will make you a far better-informed client. Knowledge of this process has saved Nigerian self-builders millions of naira in unnecessary contractor markups and overspending.

What You Need Before You Start Taking Off

You cannot prepare a reliable BoQ without complete working drawings. Attempting to measure quantities from a sketch plan or a rough layout is one of the most expensive mistakes in Nigerian construction. The drawings you need are:

• Architectural floor plan (dimensioned): Shows room layouts, wall positions, all door and window locations with exact sizes, and overall building dimensions. Every wall must have a stated length and height.
• Elevations (all four sides): Show wall heights, window sill and head levels, roof pitch, and eaves projection. Without elevations you cannot accurately calculate block quantities or roof areas.
• Building section: Shows the internal floor-to-ceiling height, foundation depth, and the relationship between floor levels. Critical for calculating plaster and tile quantities.
• Structural engineer's drawings: Show foundation type, dimensions, and reinforcement; column sizes and spacing; beam depths and reinforcement schedules; and ground slab specification. Without structural drawings, foundation and structural frame quantities are guesswork.
• Specification document: Describes the exact materials to be used at each stage. For example: "External walls: 9-inch hollow sandcrete blocks laid in 1:6 cement-sand mortar; columns: 250x250mm RC (1:2:4) with 4-Y12 bars and Y8 links at 200mm centres." If you do not have a written specification, write one before you start the BoQ.

Step 1 — Understand the Standard Nigerian BoQ Structure

Nigerian Quantity Surveyors take off and price work in the order it is built, from the ground upward. This approach — known as the "natural order of taking off" — ensures nothing is missed and makes the BoQ easy to use as a cost control document during construction. The standard sections for a residential building are:

1. Preliminaries: Site setup, temporary works, plant and equipment, insurance
2. Substructure: Excavation, hardcore, blinding, foundation concrete, DPC, ground slab
3. Superstructure: External block walls, internal partitions, RC columns, ring beams, lintels
4. Roof: Wall plate, trusses, purlins, roof covering, gutters, flashings
5. Joinery: External and internal doors, windows, louvres, burglar-proofing
6. Internal finishes: Wall plaster, ceilings, floor screed, floor and wall tiles, paint
7. External finishes: External render, external paint, damp-proof treatment
8. Plumbing and drainage: Cold water supply, hot water system, sanitary fittings, drainage, septic tank
9. Electrical: Conduit, wiring, light fittings, sockets, distribution board, earth system
10. External works: Fence and gate, paving, borehole, generator shed, landscaping

Step 2 — Take Off Quantities for Each Section

Taking off means measuring quantities from the drawings and recording them in a dim-sheet (dimension sheet). Each line of the dim-sheet shows: timesing column (number of times), length, width, depth or height, and a description. Here are the key measurement techniques for the most critical sections:

Blockwork Measurement

Measure the gross wall area in m² (height x total length for each wall type), then deduct window and door openings. For 9-inch hollow sandcrete blocks:

• One block face (including mortar joint): 450mm x 225mm = 0.101 m²
• Blocks per m² of wall = 1 divided by 0.101 = approximately 9.9 blocks per m²
• Add 5 percent for wastage and cutting

For a 3-bedroom bungalow with 380 m² of net external wall area and 120 m² of internal partition wall area: external blocks = 380 x 9.9 x 1.05 = approximately 3,950 nine-inch blocks; internal blocks = 120 x 9.9 x 1.05 = approximately 1,250 six-inch blocks. Always measure separately below and above the DPC as below-DPC blockwork often uses a stronger 1:4 mortar mix.

Concrete Work Measurement

All concrete is measured in m³ (volume). For a strip foundation: measure the total centre-line length of all foundation strips, multiply by the strip width and depth (taken from structural drawings). Example: total strip length 95 metres, width 600mm, depth 450mm = 95 x 0.60 x 0.45 = 25.65 m³. Never round up — the concrete supplier will charge for actual m³ delivered.

Roof Measurement

Roofing is measured on the slope, not the plan area. To convert plan area to slope area, multiply by the secant of the pitch angle. Common roof pitches in Nigeria and their secant values:

Measure ridges, hips, and valleys separately in linear metres, and price gutters and downpipes separately.

Floor Tiling Measurement

Measure net internal floor area in m², deducting walls (use internal room dimensions from the floor plan). Add 10 percent for wastage on plain tiles and 15 percent for diagonal or pattern-laid tiles. Always measure wall tiling separately from floor tiling — the fixing method and rates differ.

Step 3 — Price Each Item at Current 2026 Nigerian Market Rates

After measuring quantities, apply unit rates to each item to calculate costs. A unit rate has two parts: materials and labour. Here are current benchmark rates for the most common items:

Step 4 — Assemble the BoQ Document

The standard Nigerian BoQ format has six columns in the main body: Item Reference, Description, Unit, Quantity, Rate (₦ per unit), and Amount (₦). Each work section has a subtotal line, and all subtotals are carried to the Summary Page. The Summary Page should also include:

• Contingency allowance — 10 to 15 percent: Essential for Nigerian construction where price rises and unforeseen site conditions are common. Never negotiate this out of a BoQ — it is not a discretionary item.
• Contractor's overheads and profit — 8 to 15 percent: If tendering to a main contractor rather than managing trades directly, add this to account for the contractor's site management, financing costs, and profit margin.
• Professional fees: Architect 3 to 5 percent, Quantity Surveyor 2 to 3 percent, Structural Engineer 1 to 2 percent of construction value.
• Statutory fees: Building plan approval, development levies, COREN registration fees — typically ₦200,000 to ₦1,000,000 depending on plot size and local government area.

Step 5 — Review and Verify Before Tendering

Before issuing the BoQ to contractors, carry out these essential checks:

• Check all arithmetic: A BoQ with calculation errors undermines your credibility and leads to contractor disputes. Use a spreadsheet and have a second person check every section total.
• Cross-reference quantities against drawings: Pick three or four critical items — block count, roof area, floor tile area — and verify the quantities against the drawings manually.
• Verify rates are current: Call at least two material suppliers in your city to confirm current cement, block, and iron rod prices before finalising the BoQ. Nigerian material prices move quickly.
• Ensure the specification matches the rates: If you specify 60x60cm Italian porcelain tiles in the specification but price using 60x60cm local ceramic rates, your BoQ will be systematically underpriced for that section.

The 5 Most Common BoQ Mistakes Nigerian Self-Builders Make

1. Using prices that are 12 to 18 months old. Nigerian construction material prices change every 3 to 6 months. A BoQ priced 18 months ago may be 40 to 80 percent out of date. Always reprice with current market rates before tendering.
2. Omitting external works entirely. The fence, gate, septic tank, borehole, generator shed, and paving typically add ₦2M to ₦8M to a project and are often completely absent from initial BoQs.
3. Forgetting preliminaries. Site clearance, scaffold, concrete mixer hire, and temporary fencing add 3 to 5 percent to project value. When they are absent from the BoQ, contractors either load the cost into other rates (making them impossible to check) or claim them as extras at the end.
4. Undercounting blocks. Many self-builders count only the blocks visible in the superstructure on the floor plan. The full count must include substructure blocks (below DPC), gable-end triangular walls, all internal partition walls, and parapet walls around the roof perimeter where applicable.
5. No contingency provision. Nigerian construction virtually never finishes on budget without a contingency. Allow a minimum of 10 percent — preferably 15 percent on first-time builds or projects on previously untested ground.

Should You Hire a QS or Use a BoQ Tool?

For projects above ₦15 million, a professional Quantity Surveyor is worth the fee (typically 2 to 3 percent of construction value). A QS produces a complete, legally defensible BoQ, handles tendering management, monitors costs during construction, and prepares the final account. For smaller residential projects or for getting a detailed preliminary budget before committing to full drawings, our free Nigeria BoQ Generator produces an itemised Bill of Quantities in minutes — based on your house design, location, and finish level.