What a bill of quantities should contain, and what to refuse

A bill of quantities is the single most useful document in construction procurement, which is why the label gets attached to things that are not one. If you are about to tender on a document described as a BOQ, these are the things it must contain.

1. Preliminaries, as a section

Preliminaries are the costs of running the job rather than building it: site supervision, temporary facilities, insurance, security, cleaning, and the contractor's overhead and profit. A BOQ without a preliminaries section forces every tenderer to bury these costs somewhere else, which makes their prices impossible to compare and impossible to negotiate.

2. Work sections in construction sequence

A proper bill is organised by trade or work section, and the good ones follow the order in which work happens: substructure, frame, walling, roofing, finishes, services, external works. That sequence matters practically, because it aligns the bill with the valuation cycle and the materials programme. A bill organised alphabetically, or by room, is usually a spreadsheet that has escaped.

3. Measured items, not lump sums

Each item should carry a description, a unit and a quantity. Watch for "item" or "allow" or "lump sum" appearing too often. A lump sum is legitimate where work genuinely cannot be measured in advance, such as a connection to a utility whose terms are unknown. A bill that is 40% lump sums is not a bill; it is a price list, and it will not protect you from variations.

4. Descriptions precise enough to prevent argument

"Concrete" is not a description. "Concrete grade 25 in columns, including formwork and reinforcement" is. The test to apply is simple: could two different contractors read this line and deliver the same thing? If not, the description is doing no work.

A practical checklist for any measured item: material, grade or quality, thickness or size, location or element, and what is included in the rate.

5. A stated measurement basis

Quantities must be measured to a stated standard, and the standard should be named. Without one, disputed lines have no referee. Equally important in Nigeria: waste and laps must be shown as stated allowances rather than hidden inside a rate, so that a client can see where the bill is generous and where it is tight.

6. Assumptions drawn out, not buried

No drawing set is complete. A good bill carries a short list of what was assumed where the information was missing or contradictory, so that the assumption can be corrected and the quantities revised. A bill that hides its assumptions will produce variations that look like contractor errors.

What to refuse

• A priced material list called a BOQ. Materials only, no labour, no preliminaries, no measurement basis.
• Area-based quantities. If blockwork is measured as "area of building × 2.6" rather than from elevations, the figures are guesses.
• No rates column. Blank bills are fine for tender; a bill that cannot be priced line by line cannot be compared.
• No date. Rates and prices move in Nigeria. A BOQ without a date cannot be assessed for currency.
• No signed authorship. Whoever prepared it should be identifiable and prepared to defend it line by line.

What a good BOQ buys you

Three things, none of them abstract. Comparable tenders, because every contractor bids the same measured scope. Defensible variations, because a change becomes a measured quantity at an agreed rate instead of a negotiation. And payment control, because every valuation has a baseline to be tested against.

On a modest Nigerian bungalow, the fee for a proper BOQ is typically a small fraction of the cost of a single serious variation dispute. It is the cheapest control you will ever buy.