When you ask three contractors for a price on the same building, you expect three numbers you can compare. In practice, you usually get three lump sums in vastly different shapes, with no way to know what is actually different between them. The cheap one might be cheap because it skips reinforcement. The expensive one might be expensive because the contractor padded the rates.
The Bill of Quantities — BOQ — is the document that fixes this. A real BOQ breaks the cost down to a level where you (or a quantity surveyor) can compare apples to apples. Here is what a real one contains.
The five sections every BOQ must have
- Preliminaries: site setup, hoarding, water and power on site, insurance, performance bond.
- Substructure: excavation by cubic metre, blinding, footings, ground beams, hardcore filling.
- Superstructure: RC frame (concrete by m³, formwork by m², reinforcement by tonne), masonry by m², slabs, roof.
- Finishes: plaster, screeds, tiling, joinery, painting — each by m² with a specification.
- External works & services: drainage, paving, perimeter walls, plumbing, electrical, gates.
What every line should show
- A description — specific enough that a different contractor pricing the same line cannot misinterpret it.
- A quantity (m³, m², kg, tonne, number).
- A rate (per unit).
- An amount (quantity × rate).
- A material specification (e.g. C25 concrete, Y12 reinforcement, 100mm hollow block).
Red flags in a BOQ
These are not necessarily fraud, but they are signs the document is not doing its job:
- "Lump sum" or "as per discussion" instead of a quantity and rate.
- Missing reinforcement schedule (the steel cost should be in tonnes, broken down by bar diameter).
- No spec on concrete grade — "concrete" with no C-number means the contractor will pour whatever is cheapest on the day.
- No allowance for variations (typically 5–10% contingency).
- Preliminaries bundled into substructure (this hides the cost of getting the site ready and makes comparison impossible).
How to use the BOQ during construction
A BOQ is not a one-time document. It is the contract referee. Each month, your contractor should submit an interim payment certificate keyed to the BOQ — showing how much of each line has been done, and claiming payment proportional to that. You (or your clerk-of-works) verify against the work on site. If line 4.7 is "RC frame to first slab" at 18 million shillings, and only the columns are up, you pay 30%, not 100%.
No BOQ, no fair comparison. No BOQ, no controllable build. It is the cheapest part of the project to get right — usually 0.5–1.5% of project cost — and the most expensive part to skip.
