A Bill of Quantities is supposed to be the financial backbone of your construction project — a complete, itemised schedule of every material, unit rate, and labour cost. In theory, it lets you compare quotes apples-to-apples and budget with confidence.
In practice, BOQs are rarely as clean as they look. Here are the issues an independent review catches before they become expensive problems.
Omissions That Become Variations
The most common — and most costly — BOQ problem is omission. A subcontractor's scope is quietly missing from the schedule. A provisional sum covers something that should have been priced. A drainage item is under-measured. Each one looks minor on paper, but once construction starts, every omission becomes a variation — and variations are where margins erode.
An independent review cross-references the BOQ against the drawings and specifications to identify what's missing before you sign.
Duplicate or Overlapping Items
When the same work appears under two different trades — say, concrete finish in the structural section and again in the architectural section — you can end up paying twice. It's an easy mistake to make in a complex BOQ, and an easy one to miss during a busy tender period.
Vague Descriptions
"Concrete works as required" or "finishes to match existing" are red flags. Vague descriptions leave room for interpretation — and that interpretation usually favours the builder, not you. A review flags every ambiguous line item and recommends clearer language.
Unrealistic Unit Rates
Sometimes a BOQ looks complete but hides risk in the rates. A unit rate well below market might win the tender, but it often signals a contractor who plans to recover margin through variations and claims later. A review benchmarks rates against current market data.
The Bottom Line
A BOQ review typically pays for itself many times over by catching issues before they become variations. The earlier you review, the more leverage you have to negotiate.