7 Red Flags Hiding in Builder Quotes (and How to Catch Them)
From mystery PC sums to 'subject to dig' foundations — the lines in a quote that quietly cost homeowners thousands.
A bad quote rarely looks bad. It looks clean, short and competitive — and that's exactly the problem.
1. PC sums set artificially low
A "Prime Cost" sum of £3,000 for a family bathroom or £6,000 for a kitchen is fantasy. When you spec what you actually want, the variation lands like a brick. Push for realistic PCs — or supply the items yourself.
2. "Foundations subject to dig"
This is fine only if there's a stated contingency (e.g. "+£X if depth exceeds Y"). Otherwise it's an open cheque the day the digger starts.
3. No mention of VAT
Always ask: "Is this quote inclusive of VAT?" A 20% surprise at invoice time has ended more projects than bad weather.
4. Single-line totals
"Loft conversion — £62,000" tells you nothing. Demand a breakdown by trade or stage. If they refuse, they either don't know their numbers or don't want you to.
5. Front-loaded payments
A 40–50% deposit before any work starts is a major red flag. Reasonable structures are 5–15% mobilisation, then stage payments tied to completed and inspected milestones.
6. No allowance for making good
Extensions, lofts and rewires all leave damage behind. If "making good" isn't a line, expect to pay for it twice.
7. The number is way below the market
If a quote is 20%+ under the median for your postcode (check on Build Price IQ), it's either a mistake, a missing scope, or a hook for variations later.
The fix
Get the quote restructured into trade-level lines, then run it against the Build Price IQ cost checker. If anything doesn't reconcile, ask the builder to walk you through it before you sign.