How to read a builder's quote (and spot the red flags)

What a good quote includes, and the questions to ask before you sign

Buildcostr.ai · June 2026 · 6 min read

Quote vs estimate

First, know which one you are holding. A quote is a fixed price the builder is committing to. An estimate is an educated guess that can change. The two words are often used loosely, so confirm in writing whether the figure is fixed — and what could make it move.

What a good quote includes

• An itemised breakdown by work section, not a single lump sum
• Preliminaries — scaffolding, skips, welfare, insurance and supervision
• A clear labour and materials split where possible
• A schedule of payments tied to stages of work
• The builder's VAT status and whether VAT is included
• A start date, rough duration and what happens if the job overruns

The biggest red flags

A single lump sum with no breakdown. If you cannot see what you are paying for, you cannot compare quotes or challenge an overcharge.

No preliminaries. Scaffolding, skips and insurance are real costs. If they are missing, they have either been hidden in the rates or they will appear later as extras.

A large upfront deposit. A reasonable deposit covers initial materials; a demand for a big share of the total before work starts is a warning sign.

Open-ended day rates. Day rates with no cap or estimate of days can run away quickly. Ask for a not-to-exceed figure.

Provisional sums and PC sums

A provisional sum is an allowance for work that is not fully designed yet — say £4,000 for landscaping. A prime cost (PC) sum is an allowance for items you will choose later, like tiles or sanitaryware. Both are normal, but too many large provisional sums mean the quote is really an estimate in disguise.

How to compare quotes fairly

Make sure every builder is pricing the same scope — the same specification, materials and finishes. The cheapest quote is not the best one if it has quietly left things out. The most reliable way to judge any quote is against an independent cost plan of your own. Buildcostr.ai gives you that benchmark in 30 minutes. See a sample cost plan or order one before you compare quotes.

Builders can avoid the other side of this problem too — read why builders lose money on residential jobs.