Homeowners · Choosing and checking

How to choose a builder in London

A few simple checks before you hire a builder can prevent many problems. This guide walks through them in order, with a link to the official source for each point.

Information, not legal advice. This guide explains official rules in plain words for England, with links to the sources. Rules change and every job is different, so check the source or get advice for your situation. Last checked 24 October 2026.

1. Be clear about the job first

Write down what you want done, in plain words, before anyone quotes. Builders can only price what they can see. A short brief (rooms, sizes, finishes, what you will buy yourself) makes quotes easier to compare.

Check early whether you need permission. That might be planning permission, building regulations approval, or a party wall notice to your neighbours. In London, terraced and semi-detached homes often share walls, so the Party Wall Act comes up a lot. See planning, building regulations and party walls.

If you are a leaseholder, live in a conservation area or a listed building, or have restrictive covenants or a mortgage, Citizens Advice says to check whether you need anyone else's permission first (Citizens Advice).

2. Get at least three written quotes

Citizens Advice recommends getting written quotes from at least three traders (Citizens Advice). A quote is a fixed price. An estimate is a rough guess and can change. Ask for a quote, in writing. See quotes and contracts for what a good quote includes.

3. Check who you are dealing with

• Full name and a postal address. Citizens Advice says to be wary if a trader only gives a mobile number, because they might be hard to contact if problems come up (Citizens Advice).
• Limited companies are listed free on Companies House. You can see the registered office, the directors, whether the company is active, and whether its accounts are filed (GOV.UK). A sole trader or partnership will not appear there. That is normal, but it makes the other checks more important.
• Trade scheme membership should be checked on the scheme's own website, not just from a logo on a van or a flyer (Citizens Advice). The Federation of Master Builders warns that some builders claim membership they do not have (FMB).

4. Talk to past customers

Ask for two or three recent jobs similar to yours, and contact those customers yourself (Citizens Advice). Ask whether the job finished on time and on budget, how extras were handled, and whether they would hire the builder again. If you can, look at the work.

5. Check insurance and registrations

• Public liability insurance covers damage or injury to other people and property. Ask to see the certificate and check the dates (Citizens Advice).
• Employers' liability insurance is a legal requirement for most businesses with employees (GOV.UK).
• Gas work must be done by a Gas Safe registered engineer (Citizens Advice). You can check the register at Gas Safe Register.
• Electrical work should be done by a registered electrician. A competent person scheme member can self-certify the work under building regulations (GOV.UK). LABC Front Door can help you find one or your local building control.

6. Agree everything in writing

Before work starts, get a written contract with the price, the scope, the start and finish dates, a payment schedule, and how changes will be handled. Pay in stages, not upfront. See paying a builder safely.