How to Check If a Builder Is Legit in the UK (2026 Guide)

Hiring a builder is one of the biggest financial decisions you'll make as a homeowner. Get it right and you'll have quality work that lasts decades. Get it wrong and you could be looking at thousands of pounds in remedial work, legal disputes, and months of stress.

The good news? Checking whether a builder is legitimate isn't complicated — you just need to know where to look. This guide walks you through every step of verifying a builder in the UK, from initial checks to the questions you should ask before signing anything.

How to check a builder (5-minute checklist)

If you want to check a builder before they come round to quote, or before you say yes to one, these five checks take about five minutes between them. Each one uses a free, official register rather than the builder's own website, which is the whole point.

1. Look the company up on Companies House. If they trade as a limited company, search the exact name on the Companies House register. It's free and shows the registered address, when the company was set up, current and past directors, filed documents and any insolvency information (GOV.UK). A company set up a few weeks ago, or accounts that are overdue, is worth a polite question. Sole traders won't be listed, so ask for a trading address and an email as well as a mobile number.
2. Check any trade body logo on the trade body's own site. The Federation of Master Builders has a "Check a Member" search on fmb.org.uk, and warns that some businesses claim to be members when they aren't. TrustMark has its own "Find a tradesperson" search on trustmark.org.uk and advises checking the business is registered for the specific trade you need.
3. Check the registrations that the law cares about. Anyone working on gas appliances in a home must be on the Gas Safe Register. Their ID card lists what they're qualified to work on, and you can check the card number on the Gas Safe Register website (HSE). For electrics, boilers, replacement windows and some roofing, ask which competent person scheme they're registered with (NICEIC, NAPIT, FENSA, CompetentRoofer and others) and check it on that scheme's site (GOV.UK).
4. Ask for the insurance certificate and read it. Check that the business name matches the quote, the policy is in date and the public liability cover suits the size of the job. A policy number on its own doesn't tell you any of that.
5. Check the reviews properly and speak to two recent customers. There's more on how to do this in the section on checking builder reviews below.

If all five come back clean, you know the builder is who they say they are. You don't yet know whether the quote is complete or the price is fair. That's a separate check: our free builder quote checker scores a quote in a couple of minutes.

Why Checking Your Builder Matters

More than one in four UK adults who had home improvement work done in the past 18 months ran into problems, from projects abandoned halfway through to builders disappearing with upfront payments, according to research the government cited in August 2026 (GOV.UK). The construction industry has lower barriers to entry than many people realise, and there's no legal requirement for a builder to hold specific qualifications to operate in the UK.

That's why doing your homework is essential.

Step 1: Check Their Business Registration

Every legitimate builder should be a registered business. Here's how to verify:

• Companies House — If they claim to be a limited company, search for them at Companies House. Check their incorporation date, registered address, and whether their accounts are up to date.
• Self-employed — Many smaller builders operate as sole traders. Ask for their UTR (Unique Taxpayer Reference) number. A legitimate sole trader will have one.
• VAT registration — If a builder's turnover exceeds £90,000 (the threshold since April 2024), they must be VAT registered. If they're quoting large jobs without VAT, ask why.

Red flag: A builder who can't provide any business registration details or insists on cash-only payments.

Step 2: Verify Trade Body Memberships

Trade body membership isn't mandatory, but it's a strong trust signal. The most reputable ones include:

• Federation of Master Builders (FMB) — Members pass a vetting and inspection process before they join. Check membership with the FMB's Check a Member search.
• National Federation of Builders (NFB) — Represents larger building companies.
• Guild of Builders and Contractors — Members must pass financial and quality checks.
• TrustMark — The Government Endorsed Quality Scheme for work in or around the home. TrustMark says its registered businesses are thoroughly vetted to meet required standards and have made a commitment to good customer service. Check the business is registered for the specific trade you need.

How to verify: Don't just take their word for it. Go to the trade body's website and search for the builder by name. Membership logos on a van or website can be faked — the official directory cannot.

Step 3: Check Their Insurance

A legitimate builder should carry at minimum:

• Public liability insurance — Covers damage to your property or injury to third parties. A minimum of £2 million cover is standard; £5 million or £10 million for larger projects.
• Employer's liability insurance — Required by law if they employ anyone. Must be at least £5 million.
• Professional indemnity insurance — Not always standard but important for design-and-build work.
• Contract works insurance (All Risks) — Covers the building work itself against damage during construction.

Ask to see certificates, not just policy numbers. Check the policy dates are current and that the cover amount is appropriate for your project size.

Step 4: Look at Their Track Record

• Google Reviews — Search their business name on Google. Look for a consistent pattern of positive reviews over time, not just a handful of 5-star reviews posted in one week.
• Checkatrade / MyBuilder / Rated People — These platforms run their own checks on tradespeople and collect customer reviews. Check their profile history and read the detailed reviews, not just the star ratings (see how to check builder reviews, below, for what these sites can and can't tell you).
• Ask for references — A confident builder will happily provide contact details for 3-5 recent customers. Call them. Ask specifically: Did the builder finish on time? Were there unexpected costs? Would you use them again?
• View previous work — Ask to see completed projects in person, not just photos. A builder who's proud of their work will welcome this.

Step 5: Check Their Qualifications

While there's no single mandatory qualification for builders in the UK, these credentials demonstrate competence:

• NVQ/SVQ Level 2 or 3 in a relevant construction trade
• CSCS card (Construction Skills Certification Scheme) — Shows they've passed health and safety tests
• City & Guilds qualifications in their specialist area
• Electrical competent person scheme registration (such as NICEIC or NAPIT) — Lets an electrician self-certify notifiable electrical work under Part P of the Building Regulations
• Gas Safe registration — Legally required for any gas work

For specialist work, always check the specific certification. Notifiable electrical work must either be done by someone registered with a competent person scheme or be signed off by building control. Gas work must only be done by Gas Safe registered engineers.

Step 6: Get Everything in Writing

A legitimate builder will provide:

• A detailed written quote (not just an estimate) breaking down labour, materials, and VAT
• A written contract covering scope of work, payment schedule, start and completion dates, and what happens if things change
• A payment schedule tied to milestones, not upfront lump sums
• Details of any warranties or guarantees on their work

Keep any deposit small: 5-10% is normal, or nothing at all. Established builders have trade accounts with their merchants, so if materials really need paying for up front, offer to pay the merchant directly. After that, pay for completed stages of work. A builder demanding 30% or more before starting is a major red flag.

Step 7: Trust Your Instincts

Beyond the paperwork, pay attention to:

• Communication — Do they respond to calls and messages promptly? Are they clear and professional?
• Punctuality — If they're late to the quote meeting, they'll likely be late to the job.
• Willingness to explain — A good builder will happily walk you through what they're planning and why.
• Pressure tactics — "This price is only valid today" or "I've got another job starting next week" are classic pressure signs. A busy, legitimate builder doesn't need to pressure you.
• Too good to be true — If one quote is dramatically lower than others, ask yourself why. They might be cutting corners on materials, using unqualified labour, or planning to add costs later.

The Quick Verification Checklist

Use this checklist before hiring any builder:

• ✅ Registered business (Companies House or sole trader UTR)
• ✅ Trade body membership verified on official website
• ✅ Public liability insurance certificate (current)
• ✅ Employer's liability insurance (if they have employees)
• ✅ At least 3 contactable references from recent projects
• ✅ Consistent positive reviews across multiple platforms
• ✅ Relevant qualifications and CSCS card
• ✅ Detailed written quote with full breakdown
• ✅ Written contract before work begins
• ✅ Reasonable payment schedule (not heavy upfront)

How to check builder reviews (and spot fake ones)

Reviews are the first thing most people look at, and the easiest thing to game. Fake reviews have been banned in the UK since 6 April 2025, and businesses and review platforms now have a legal duty to take steps to prevent and remove them (GOV.UK). That helps, but some will still get through. Here's how to read reviews the way another builder would:

• Check more than one place. Look at Google, any directory profile (Checkatrade, MyBuilder, Rated People, TrustMark) and local Facebook group recommendations. The same picture across several places counts for more than a perfect score on one.
• Read the 3- and 4-star reviews first. They're usually the most honest, and they show you how problems were handled.
• Look at the dates. A steady trickle over several years is normal. A burst of five-star reviews in the same week and then nothing is worth noticing.
• Look for detail that matches real jobs. Genuine reviews tend to mention the type of work, roughly where it was, how long it took and who did it. "Great job, highly recommend" repeated with no detail tells you very little.
• Check who wrote them. On Google you can usually tap a reviewer's name to see their other reviews. An account that has only ever left one review is weaker evidence than one with a long, ordinary history.
• See how the builder answers criticism. Every builder gets the odd poor review. A calm, specific reply that explains what they did about it is a good sign.
• Ask for addresses, not just reviews. Ask for two or three recent jobs like yours and, if the owners are happy to, go and look. Ask whether the job finished on time, whether the price moved and whether they'd use the builder again.

If something looks off, report it to the platform it's on. Then rely on the checks that can't be faked: the registers, the insurance certificate and the finished jobs you've seen.

Who checks builders' work in the UK?

Nobody checks every builder. There's no licence needed to work as a builder in the UK, and the Federation of Master Builders is campaigning for one (FMB). What you get instead is a patchwork, and each part checks something different:

• Building control. For work covered by the Building Regulations, such as extensions, structural alterations and new drainage, a building control body checks that the work meets the regulations. That's either your council's building control team or a private registered building control approver, which used to be called an approved inspector (GOV.UK). They inspect at key stages and issue a completion certificate at the end (an approver issues a final certificate), which you'll usually be asked for when you sell. A completion certificate isn't a guarantee of workmanship (St Albans City and District Council): it covers compliance, not the finish or value for money. Ask who is making the building control application before work starts. Scotland and Northern Ireland have their own systems.
• Competent person schemes. Registered installers can self-certify certain work, including electrics, heating, replacement windows and doors and some roofing, instead of going through building control. The government authorises these schemes (GOV.UK), and you should get a certificate at the end. Gas work must be done by a Gas Safe registered engineer (HSE).
• Companies House. It records that a company exists and what it has filed. It doesn't check the quality of anyone's work.
• TrustMark. TrustMark describes itself as the Government Endorsed Quality Scheme for work in or around the home, and says its registered businesses are vetted to meet required standards (TrustMark). It's voluntary, so check the business is registered for the trade you need.
• Trade bodies such as the FMB. People sometimes search for it as the "master builders association". The Federation of Master Builders says members pass a vetting and inspection process before they join, and it offers a dispute resolution service (FMB). Membership is voluntary, so check it on the FMB's own register.
• The new Approved Code. In August 2026 the government announced a voluntary Approved Code for home improvement businesses, run by the Furniture and Home Improvement Ombudsman with the Chartered Trading Standards Institute. It's due to be fully live by December 2026 (GOV.UK). It's new, so treat it as one more thing to check rather than a guarantee.
• Checkatrade-type sites. Checkatrade, MyBuilder, Rated People and similar sites are privately run directories. Each runs its own checks and hosts reviews, which is useful. But they aren't regulators, what they check varies from site to site, and a profile shows what that platform verified, not how your job will go. Read what the profile says has actually been checked, and still do the Companies House, insurance and registration checks yourself.

If you want someone checking quality on your side as the job goes, building control won't do that for you. You can pay an independent chartered surveyor or building consultant to inspect at key stages. Whoever does the work, the law says a service must be carried out with reasonable care and skill (Consumer Rights Act 2015, section 49).

What to Do If Something Goes Wrong

If you've already hired a builder and things aren't going to plan:

1. Document everything — Photos, messages, receipts, and a timeline of events
2. Communicate in writing — Put complaints in writing (email or letter) so there's a record
3. Contact Citizens Advice — Free guidance on your rights
4. Trading Standards — Report rogue traders via your local authority
5. Small Claims Court — For disputes under £10,000 in England and Wales

How Chat to Your Builder Can Help

Not sure whether a builder's quote is fair? Worried about the quality of work being done? You can put it in front of a working builder with nearly 30 years on site. We can help you:

• Review quotes and check they're reasonable with a builder quote review. See our guide to builder quote red flags for what to look out for
• Sense-check work in progress from your photos and paperwork, to spot problems early
• Interpret RICS survey reports with a RICS survey review, so you understand what needs doing. Read more about how we help with RICS surveys
• Get realistic cost estimates before committing to a project, including extension costs across the UK

Whether you're in London, Manchester, Birmingham, or anywhere else in the UK, a written review and a call within 24 hours costs £59 and could save you thousands. Book a review.