How do I compare builders' quotes properly?

Three numbers on three pieces of paper look comparable and almost never are. Each builder has read your job differently, assumed a different scope, and priced a different set of risks. The work of comparison is not arithmetic — it is normalising three different jobs into one before you look at the money.

What you'll need

• Your own written specification, sent identically to everyone
• Three written quotes against that specification
• A single comparison sheet listing every line (optional)

Step by step

1. Send the same written specification to everyone.This is the step that makes comparison possible at all. Without it you are comparing three interpretations of a conversation, and every later disagreement about scope traces back to here.
2. Establish whether each document is a quote or an estimate.A quote is an offer of a fixed price for defined work; accepting it forms a contract at that price. An estimate is an indication and carries no such commitment. If the document does not say which it is, ask — and assume the weaker answer until told otherwise.
3. Check materials: who supplies, and to what specification."Supply and fit" against "fit only" is a large difference. So is a named product against a category. Where you are supplying, note that the risk of shortage, damage and delay moves to you.
4. Check VAT.Whether the price includes it, and whether the business is VAT registered at all. A quote excluding VAT sitting beside one including it is not a comparison, it is a trap.
5. Check making good.Plastering, decoration, reinstating skirting, filling chases, and leaving the surrounding rooms as they were. This is the single most commonly excluded item and the one people most assume is included.
6. Check waste, skips and access.Skip hire, waste transfer, and any highway licence for a skip or scaffold on the road. Scaffolding on a two-storey job is a substantial cost and it is regularly left out of the cheaper quote.
7. Check the fees and who pays them.Building control fees, planning fees, structural engineer's fees, drawings, and — in England and Wales — party wall surveyors. Each of these can be inside or outside a quote, and each is a real number.
8. Scrutinise provisional sums.A provisional sum is a placeholder for work that has not been specified and will be priced later. It is not a price — it is a decision deferred, and it is where final bills grow. A quote carrying large provisional sums is much less firm than its total suggests.
9. Check the programme and the payment schedule.Start date, duration, and what triggers each payment. A shorter programme has value and a payment schedule weighted to the front has a cost, and both belong in the comparison.
10. Add the exclusions back and compare the real totals.Put every quote on one sheet, line by line, add in what each has excluded at a realistic figure, and compare the bottom rows. The order frequently reverses.
11. Ask the outlier why.Both the highest and the lowest. The high one may have seen something the others missed; the low one may have missed something the others saw. That conversation is often the most useful hour of the whole process.

Tips

• Never share one builder's price with another. It produces a matched number rather than a considered one, and it tells you nothing about scope.
• A quote that fits on one line for a project worth many thousands is not a quote, whatever it is headed.
• Ask each builder what they think the risks are on your job. The answers are more revealing than the prices, and a builder who has identified a real risk has usually priced it.

Common mistakes

• Comparing totals before normalising scope — The cheapest quote is most often the one that excluded making good, waste and scaffolding. Once those are added back the ranking commonly reverses.
• Treating a large provisional sum as a price — It is an allowance for undefined work. The final figure is settled later, when you have far less leverage than you do now.

Questions people ask