How to Check if a Builder Is Legitimate UK

Hiring a builder for a home renovation involves handing over significant sums of money to someone you may have met once or twice. Unlike many other professional services, there is no mandatory licensing scheme for builders in England and Wales. Anyone can call themselves a builder and start trading tomorrow. This makes due diligence – checking that your builder is who they claim to be – your responsibility.

The good news is that the checks are straightforward, mostly free, and can be completed in an afternoon. Here is exactly what to look for and where to find it.

Check Companies House for their registered business

Start at Companies House (find-and-update.company-information.service.gov.uk). Search for the builder's company name or their personal name if they are a sole trader operating through a limited company.

You are looking for several things. First, that the company exists and is listed as "Active." A company that is dissolved, in liquidation, or has a proposal to strike off is an immediate disqualification. Second, check the incorporation date – a company registered last month carries more risk than one that has been trading for five years. Third, look at the filing history: are accounts and confirmation statements filed on time, or are there persistent late filings? Late filings suggest disorganisation at best and financial distress at worst.

Check the registered office address. If it is a residential address in a different part of the country from where the builder claims to operate, ask questions. Also note the names of the directors – if the builder you are speaking to is not listed as a director or person of significant control, find out who is and why.

If the builder is a sole trader (not a limited company), they will not appear on Companies House. This is not inherently a problem – many legitimate tradespeople operate as sole traders – but it does mean you have fewer public records to verify.

Verify their insurance cover

Any builder working on your property should carry public liability insurance as a minimum. This covers damage to your property and injury to third parties caused by the builder's work. For most residential projects, a policy of at least £2 million is appropriate; for larger projects involving structural work, £5 million or more is advisable.

Ask the builder for a copy of their insurance certificate – not just verbal confirmation. The certificate should show the policy number, the insured party's name (which should match the builder's company or trading name), the coverage amount, and the expiry date. If the policy has expired, it is worthless.

Some builders also carry employer's liability insurance (legally required if they have employees) and professional indemnity insurance (useful if they are providing design services). Check which policies they hold and whether the coverage is appropriate for the scale of your project.

Look for trade body membership

Trade body membership is not compulsory for builders in England and Wales, but it is one of the strongest voluntary signals of professionalism. The main trade bodies for residential builders include the Federation of Master Builders (FMB), TrustMark, the British Association of Landscape Industries (BALI), and the National Federation of Builders (NFB).

Each of these organisations has admission criteria that typically include proof of insurance, financial vetting, and in some cases site inspections or competency assessments. Membership can be verified directly on the trade body's website – do not rely on the builder's claim alone.

TrustMark membership is particularly worth checking because it is a government-endorsed quality scheme, and many TrustMark members offer deposit protection and insurance-backed guarantees. If your builder is TrustMark registered, you have an additional layer of recourse if something goes wrong.

Read independent reviews across multiple platforms

A builder's own website will only show positive testimonials. To get an honest picture, check independent review platforms: Checkatrade, MyBuilder, Houzz, Google Business Profile, and Bark.

Look for volume and consistency. A builder with 80 reviews averaging 4.5 stars across two platforms is a stronger signal than one with five reviews all scoring 5.0 on a single platform. Pay attention to negative reviews – not just the rating, but how the builder responded. A professional response to a complaint ("we acknowledge the issue and returned to fix it") tells you far more than a defensive or aggressive one.

Search for the builder's company name on Google alongside terms like "complaint," "dispute," or "county court." This can surface issues that do not appear on review platforms, including CCJs (county court judgments) that indicate unpaid debts or legal disputes.

Ask for references and visit a completed project

Online reviews are useful, but speaking directly to a previous client is more informative. Ask the builder for three references from projects completed in the past 12 months, and make sure the projects are comparable to yours in scope and value.

When you contact the references, ask specific questions. Did the project finish on budget? Were there unexpected costs or variations? How responsive was the builder when issues arose? Did they come back to resolve snagging items? Would you use them again?

If possible, ask to visit a completed project. Seeing the quality of the builder's work in person – the finish of the plastering, the alignment of the tiling, the neatness of the cabling – gives you information that no photograph or review can provide.

Check their VAT registration if the project is over £20,000

If your project costs more than £20,000 (including labour and materials), it is worth checking whether the builder is VAT registered. The current VAT registration threshold in the UK is £90,000 in turnover. A builder who has been trading for several years and is not VAT registered is either very small (which may be fine) or may not be declaring all of their income (which raises questions about their overall business practices).

You can verify VAT registration on the HMRC VAT registration checker. If the builder charges you VAT, their VAT number should appear on every invoice, and you can verify it is valid.

Use digital tools to assess risk before committing

The verification steps above give you a strong foundation, but they are manual and time-consuming. Digital tools can help streamline the process and identify risks you might miss.

The Renopay Risk Checker aggregates key data points about your project – the builder's credentials, the payment structure, the contract terms – and flags areas where your risk exposure is elevated. Use it alongside your manual due diligence to build a complete picture before signing a contract or paying any money.

If you are satisfied that the builder is legitimate, the next step is to protect yourself through the payment structure. Even a verified, reputable builder can encounter financial difficulty or deliver work that does not meet expectations. Milestone-based escrow services such as Renopay ensure that your financial exposure at any point matches the work completed – so that verification and payment protection work together as complementary layers of safety. For a broader look at warning signs beyond credentials, see our guide on red flags when hiring a builder.