How to Find and Vet a Builder in the UK (The Complete Guide)

Hiring the wrong builder is one of the most expensive mistakes a homeowner can make. Rogue traders cost UK consumers an estimated £2 billion a year, according to the Chartered Trading Standards Institute — and the victims are overwhelmingly people who hired without a proper vetting process. Whether you're planning a loft conversion, extension, or full refurbishment, knowing how to find and vet a builder before a penny changes hands is essential.

This guide walks you through every step: where to look, what questions to ask, what a proper quote must contain, and what to do if things go wrong.

Where to Find Reliable Builders

The best starting point is always personal recommendation from someone who has had similar work completed. Ask to see the finished job and whether it was completed on time and on budget.

Beyond that, use accredited directories:

• Federation of Master Builders (FMB) — Members are independently vetted and must pass a quality standard assessment. Find a member at fmb.org.uk.
• TrustMark — Government-endorsed quality scheme. All registered firms are checked for technical competence, customer service, and trading practices.
• Which? Trusted Traders — Endorsed by the UK's leading consumer organisation after an assessment process.
• Checkatrade / Rated People — Useful for smaller jobs but verify reviews carefully; not all platforms independently verify tradespeople.

Always get at least three quotes for any job over £1,000.

What Accreditation Actually Means

Being listed on a directory or scheme is not a guarantee of quality, but it does shift the risk. FMB and TrustMark members must:

• Hold adequate public liability insurance
• Pass competency checks
• Submit to dispute resolution if a complaint is raised

Verify membership directly on the scheme's website — do not rely solely on the trader's own claim. Ask to see their public liability insurance certificate (minimum £2 million cover for most domestic work) and their VAT registration number if the quote exceeds the VAT threshold (£90,000 from April 2024).

The 7 Questions to Ask Before Hiring

1. Can you provide references from similar projects completed in the last 12 months? Ask to contact referees directly.
2. Are you VAT registered, and will my invoice show your VAT number? Non-registration on larger jobs is a red flag.
3. Who will actually be on site — you or subcontractors? Understand who is responsible for quality.
4. What does your public liability insurance cover, and can I see the certificate?
5. How do you handle changes or unexpected work during the project? A good builder will have a clear variation process.
6. What is your payment schedule, and why? Reputable builders do not ask for large upfront payments.
7. Are you a member of a trade body or accreditation scheme? Then verify it yourself.

What a Proper Written Quote Must Include

Never accept a verbal quote. A compliant written quote should specify:

• Scope of work — detailed description of every element (demolition, materials, finishes, making good)
• Materials specification — brand, grade, and quantity where relevant
• Start and finish dates (or a realistic lead time if dates aren't confirmed)
• Payment schedule — staged milestones, not a lump sum up front
• VAT status — VAT number and whether quote is inclusive or exclusive of VAT
• Validity period — most quotes hold for 30–60 days
• Any exclusions — what the quote does not cover

Red Flags Table

Contract Basics: JCT vs Letter of Intent

Before work begins, it's also worth confirming what sign-off your project needs. Many types of renovation — extensions, structural alterations, electrical work — require building regulations approval even when no planning permission is needed. For electrical installation specifically, insist on a contractor registered with NICEIC or NAPIT — they are authorised to self-certify under Part P and must issue you an Electrical Installation Certificate on completion. Our guide to rewiring a house in the UK covers what the process involves and how to choose a registered electrician. Your builder should know this, but it is ultimately your responsibility as the homeowner to make sure the right approvals are in place.

For jobs over approximately £5,000–£10,000, a proper building contract is worth the small additional effort.

• JCT Minor Works Building Contract — The industry standard for domestic projects. Covers scope, payment, variations, defects liability period (usually 6–12 months), termination, and dispute resolution. Available from jctltd.co.uk for around £35.
• Informal Letter of Intent — Acceptable for smaller jobs. Should still specify scope, price, payment schedule, and start/finish dates in writing. Signed by both parties.

At minimum, even for a small job, confirm everything in a written email before work begins. This creates a contractual record.

Deposit Norms and Payment Milestones

Industry norms for deposits:

• Small jobs (under £5,000): No deposit is reasonable; pay on completion.
• Medium jobs (£5,000–£50,000): 10–25% deposit acceptable to cover material orders; balance in staged payments.
• Large projects: Staged payments tied to defined milestones (e.g., foundations complete, first fix complete, second fix complete, snagging resolved).

Never pay more than 25% upfront. A reputable builder does not need 50% before starting — they have a credit account with their merchant.

Retain a 5–10% retention until snagging is completed and a defects liability period has passed.

Once your builder is appointed, the real project management work begins. The guide to managing a building project in the UK covers contracts, daily site oversight, change orders, and how to handle disputes if the relationship breaks down.

What to Do When Things Go Wrong

If the relationship breaks down:

1. Document everything — photographs, emails, a dated diary of events.
2. Write a formal letter setting out your complaint and what resolution you require, with a 14-day response deadline.
3. Use the scheme's dispute resolution — FMB, TrustMark, and Which? Trusted Traders all offer free or low-cost dispute resolution for members.
4. Contact Citizens Advice / Trading Standards — Trading Standards can investigate and prosecute under the Consumer Rights Act 2015.
5. Small Claims Court (Money Claims Online) — For sums under £10,000, use the small claims track. The fee is £35–£455 depending on the claim amount. The process is designed to be used without a solicitor.

Builder Vetting Checklist

Plan Your Renovation With Confidence

Before appointing a builder, it is worth identifying any structural or damp issues in the property that the builder should know about and price for. Undisclosed problems — particularly damp in older properties — routinely cause budget overruns when discovered mid-project. Our guide on damp diagnosis and repair in older UK properties explains how to identify the three types of damp and get an independent survey before work begins.

If your project is an extension, it is worth confirming whether it falls under permitted development or requires a full planning application before you appoint anyone — the complete guide to home extension PD vs planning permission sets out the current rules for England, including the Prior Approval neighbour consultation scheme.

A reliable builder is only one part of a successful project. Renovate Me gives you a step-by-step renovation roadmap — upload photos of your home, set your goals and budget, and unlock a personalised plan that covers everything from finding the right tradespeople to managing costs at every stage. Start your renovation plan today at renovate-me.madethis.app.

For a compact guide focused on the FMB/TrustMark vetting hierarchy, the JCT Minor Works contract, and dispute resolution escalation paths, see our how to find a reliable builder UK guide.