Feature
How to Read a Quote From a Trade
Errol Nakamura · · 2 min
Two quotes for the same job routinely differ by more than the work costs. Usually neither is wrong; they have made different assumptions and only one of them has written those assumptions down.
These are the terms that carry the difference.
Allowance / provisional sum
A placeholder for work that cannot be priced yet, usually because nobody has opened the wall. It is a guess with a number next to it, and it will be reconciled against actual cost later.
A quote that is £2,000 cheaper because its tiling allowance is £2,000 lower is not cheaper. It is less specified.
Prime cost (PC) sum
A budget for a product you have not chosen — taps, tiles, a boiler. The labour to fit it is priced; the item is not. Two quotes with different PC sums are quoting different bathrooms.
Supply only vs supply and fit
Exactly what it says, and the single most common cause of a surprise. “Supply only” means the material arrives and nothing happens to it.
Also check who is responsible for getting it there, and for what is left over — waste removal is frequently excluded and frequently expensive.
Exclusions
The most informative section and the one nobody reads. Making good, decorating, scaffolding, skip hire, permits, and anything structural are the usual exclusions. A short exclusions list is not generosity; it often means they have not thought about it yet.
Comparing honestly
Do not compare totals. Line the quotes up and normalise: same PC sums, same allowances, same exclusions. Most of the gap disappears, and what remains is the real difference in labour rate and margin — which is the number you actually wanted.
If one quote cannot be normalised because it is a single line reading “bathroom — £9,500”, that is the finding.
Mortar Desk publishes general reference information about building materials and specifications. It is not a contractor and does not provide engineering advice. Work involving gas, structural elements or main electrical supply belongs to a licensed trade, working to local code.