Costs & budgeting
Understanding Bills of Quantities (BOQs)
A Bill of Quantities (BOQ) is a document that lists every measurable item of work needed to build a project, with its quantity and unit. Priced, it becomes the backbone of your budget, your contract and your payments.
What a BOQ contains
- Preliminaries — site setup, insurances, temporary works, supervision and other general items.
- Measured work — grouped by element (substructure, walling, concrete, roofing, finishes, services) with quantities in m³, m², m, kg or number.
- Provisional sums — allowances for work that can't yet be measured precisely.
- Prime cost sums — allowances for items to be selected later, such as sanitary fittings.
- Contingency — a reserve for genuine unforeseen work.
Why it matters
Comparing quotes fairly
When every contractor prices the same BOQ, you compare like with like. Without one, each contractor prices their own interpretation of your drawings and the cheapest quote is often the one that left the most out.
Controlling payments
Interim payments can be valued against BOQ items actually completed, rather than estimates of percentage complete.
Managing changes
Rates in the BOQ give an agreed basis for pricing variations when the design changes.
How to read one
Look for completeness first: are external works, plumbing, electrical and finishes all included? Check that quantities look sensible for the size of building. Then look at rates: unusually low rates on early items and high rates on later ones can be a sign of front-loading.
Remember: a BOQ is only as good as the drawings it is measured from. If the design is incomplete, expect provisional sums — and expect them to change.
Who prepares a BOQ? In Kenya, quantity surveying is a registered profession. For larger or contractual BOQs, involve a registered quantity surveyor. We prepare and review BOQs within our qualifications and coordinate with QS professionals where the project requires it. See cost control and BOQs.
This article is general guidance for property owners in Kenya and is not a substitute for professional advice on your specific project. Regulations, requirements and prices change — confirm current details with the relevant authority or professional.
