How to Check a Builder Is Legitimate in Ten Minutes

In short: you can check whether a builder is legitimate in about ten minutes, for free, using eight sources: the builder's own details, Companies House, the disqualified directors register, the register for the trade (Gas Safe, NICEIC or NAPIT, FENSA or CERTASS, HETAS), TrustMark, the Federation of Master Builders, the insurance certificate, and reviews read across more than one platform. Run them in that order, because each gives you the name or number the next one needs. None of them tells you whether the quote is complete, so the last step is to check the quote itself.

There is no statutory licence you must hold to trade as a general builder anywhere in the UK, so no register proves a builder is allowed to work. What exists instead is a set of separate registers, each covering one thing, and a builder who is what they say they are passes all of them without fuss. This guide takes each in turn: where to go, what to type, and what a pass and a fail look like.

The eight checks and how long they take

Ten to twelve minutes once you have the details. If getting them takes days, that is a result in itself.

1. What you need from the builder

Everything else depends on this step, so do it first and do it in writing. Ask for:

• The exact legal name of the business, and the company number if it is a limited company
• The trading name on the van and the quote, if that is different
• The registered address, or the trading address for a sole trader
• The name of the person you are dealing with, and whether they are a director
• A copy of the public liability insurance certificate, not a policy number
• The registration numbers for any trade scheme they claim: Gas Safe, NICEIC, NAPIT, FENSA, CERTASS, HETAS, TrustMark, FMB

A legitimate firm has all of this to hand and sends it the same day. A first name, a mobile number and "we're all registered, don't worry" is the fail, and so is a company number the builder cannot find. Our guide to five things to check before hiring a builder covers the wider conversation; this post is about what to do with the answers.

2. Companies House

Search the name or the number at Companies House. The search box takes company names, company numbers and officer names, so you can search the director as well as the firm. Everything you need is free: the registered address and date of incorporation, current and resigned officers, previous company names, and insolvency information.

Status. It should say Active. Dissolved or in liquidation is a stop until you understand why. Watch for the note that sits beside the status: a company facing strike-off still reads Active, with "Active proposal to strike off" alongside it, and that is a stop too.

Incorporation date against claimed years. "Twenty years in the trade" and a company incorporated eighteen months ago is not necessarily a lie, but ask what happened to the previous business. Sometimes the answer is a sole trader who incorporated last year. Sometimes it is the next item.

Previous names. The company overview lists them. Reviews under the old names are part of the firm's record.

Directors. Open the People tab; the person you are dealing with should be there. Then search that director's name on its own, because Companies House lists every company a person is or was an officer of.

The phoenix. A director with a run of dissolved companies, often at one address, each replaced by a new one with a similar name. Debts, disputes and unfinished jobs stay in the dead company and the same people carry on trading. Our guide to rogue builders and how to spot them explains phoenix companies, and our post on a builder going bust mid-job shows the other side of the pattern.

Then search the register of disqualified company directors by surname; the gov.uk page links through to the searchable register Companies House runs at find-and-update.company-information.service.gov.uk. A record shows the person's name and date of birth, the disqualification type and the dates it runs between, the company whose conduct caused it, the reason, and whether a court has given permission to act as a director anyway. Any entry is a stop, whatever the reason.

A sole trader's business will not be registered at Companies House, and that is normal: Companies House registers limited companies, not sole traders, who register with HMRC instead. So a blank search is not itself a red flag. Search the person's own name as well, because a sole trader can still appear as a director of some other company or on the disqualified register. It also means the insurance check and the trade registers carry more weight, and you should have a trading address.

3. The register for the trade

This is the check most people skip, and the one with legal weight behind it. For the regulated trades on your job the person doing the work must be registered, and each register is free to search.

Gas: Gas Safe Register. Go to gassaferegister.co.uk and use Check. A business is checked by its registration number (1 to 6 digits) or trading name; an engineer by the 7-digit licence number on their Gas Safe ID card. Gas Safe issues a new card every year with a different licence number, so last year's number will not match. On the day, ask to see the card: it lists the types of gas work the engineer is qualified for, and not every engineer is qualified for every appliance.

Electrics: NICEIC, NAPIT and the other competent person schemes. In England, notifiable electrical work means a new circuit, a consumer unit replacement, or an addition or alteration to an existing circuit in a "special location" (the zone around a bath or shower, or a room containing a swimming pool or sauna heater). It must be certified by one of three routes: an electrician registered with a government-authorised competent person scheme, a registered third-party certifier, or building control. Wales works differently: the narrowed England list does not apply there, so adding to or altering a circuit in a kitchen or outdoors is notifiable in Wales when it is not in England. NICEIC and NAPIT are the names you will see most, but one search covers every scheme: electricalcompetentperson.co.uk is the single electrical register, searched by company name under Check an electrician. Our electrics inspection guide sets out the paperwork a registered electrician then owes you.

Windows and doors: FENSA or CERTASS. FENSA's register is at fensa.org.uk under Find an Installer, searchable by postcode, installer name or FENSA registration number. Certass runs its register at certifiedcompetent.co.uk, searchable by company name or postcode. FENSA is blunt about the point: you only get a FENSA certificate with a FENSA Approved Installer, and the certificate matters when you sell. Both schemes require the installer to register the job within 21 days of completion, and FENSA then usually issues the certificate about 15 days after that. The 30 day figure you may see quoted is the statutory backstop in regulation 20(3), not the scheme deadline.

Stoves and solid fuel: HETAS. Search HETAS's registered businesses at hetas.co.uk. A registered installer notifies the job and HETAS posts a Certificate of Compliance within two weeks of the notification reaching its system. Self-certification through a competent person scheme does not apply in Scotland, Northern Ireland, the Republic of Ireland or the Isle of Man, and HETAS says to contact the local authority in those regions before the work starts.

What registration proves, and what it does not. A register entry proves that a business or a named person holds current registration for a type of work. It does not prove that the person who turns up is that person. A registered firm can send an unregistered subcontractor, and for gas that is an offence whoever quoted. Check the firm before you sign and the individual's card on the day. Registration belongs to the person doing the work, not the firm on the letterhead.

4. TrustMark and FMB, looked up on their own sites

Both are voluntary, so a builder without them is not doing anything wrong. A builder who claims them and is not listed is telling you something. There is one exception to "voluntary": for insulation and heating measures funded under ECO4 or the Great British Insulation Scheme, the installer has to be TrustMark-registered, so on grant-funded work it is effectively compulsory.

TrustMark is the government-endorsed quality scheme for work in and around the home. Search the business name on TrustMark's own register, or search by town or postcode and the type of work. The pass is the business appearing with your trade listed against it. The fail is a TrustMark logo on the website or the van and no entry on the register. Logos are copied; the register is not.

The Federation of Master Builders runs a two-stage process before a firm can join. First the vetting: trading history and credit checks, director checks for limited companies, and proof of public liability cover. If the firm passes, an FMB assessor visits one of its sites and inspects the work. Applicants must be a UK sole trader or small construction company with at least twelve months of trading behind them. Search the builder's name on the FMB's check a member page at fmb.org.uk. The FMB itself warns that some firms claim membership when they are not members, which is why you look it up rather than take the badge on the quote.

5. Insurance

Ask for the public liability certificate and read it. Four things to check:

• The insured name matches Companies House exactly. Not a similar trading name, not the director personally while the quote is from a limited company. Cover follows the named policy holder, so if the quote comes from Smith Builders Ltd and the certificate names John Smith personally, that is a mismatch to put to the builder or the broker before work starts.
• The dates. The policy must be in force on the day work starts, and ideally through to completion. A certificate that expired last month is a fail, however friendly the explanation.
• The indemnity level. There is no legal minimum for public liability. Insurers sell it in fixed tiers, commonly £1 million, £2 million, £5 million and £10 million, but no published UK figures show where small builders actually sit, so treat a limit as something to read on the certificate rather than a benchmark to judge against. The right figure depends on the worst case for your job: a two-storey extension against a neighbour's house is not a garden wall. If the limit looks thin, ask.
• Employers' liability. Separate policy, and compulsory for almost every business that employs anyone under a contract of service. The exemptions are narrow, and the one that comes up with builders is a limited company whose only employee owns 50% or more of the shares. The minimum cover is £5 million, set by the Employers' Liability (Compulsory Insurance) Regulations 1998 and repeated on gov.uk, and a business can be fined £2,500 for every day it is uninsured. If the builder uses subcontractors, ask whether they are covered.

Our guide to protecting yourself during building work goes on from here to contracts, deposits and stage payments.

6. Reviews, cross-checked

One platform tells you very little. Read three side by side: Google, a trade directory such as Checkatrade, and local community groups. Search the trading name, the company name and the director's name, each followed by "reviews", "complaints" and "trading standards".

The pass is consistency: the same trading name everywhere, reviews spread over years rather than months, specific detail about real jobs ("the steel went in on the Tuesday and building control came Thursday" rather than "great service, would recommend"), and a sensible reply to the occasional poor one.

The fail is a burst of five-star reviews in a single month, reviews under a name that is not on Companies House, or a trail of complaints under a previous name that the current profile does not mention. Our guide to whether builder reviews are real covers the tells in detail, and our post on whether to use Checkatrade explains what a directory listing does and does not prove.

7. What none of this tells you

A builder who passes all eight checks exists, is insured, is registered for the regulated trades on your job, and has a record you can read. That is the floor, and most people never check it.

It is not the finish. None of these registers looks at the quote. A legitimate, registered, insured, five-star builder can still hand you a quote that leaves out building control fees, scaffolding, skip hire, making good and decoration, and each of those comes back as an extra once the job is under way. Missing scope is the most common reason a project runs over, and it is invisible until the quote is read line by line against what the job needs. So once the builder has passed, check the quote.

8. The printable checklist

Every register above, with its address, what to type, and what a pass and a fail look like, on one sheet.

Common mistakes

Checking the firm and not the person. Gas and electrical registration belongs to the individual doing the work. A fully registered firm can still send someone who is not. Check the card on the day.

Trusting the logo. TrustMark, FMB, Gas Safe and NICEIC logos are copied onto vans and websites by firms that hold none of them. The register is the only thing that counts.

Reading the certificate without reading the name. A policy in the director's personal name does not cover a limited company's contract, and "J Smith Building" may not cover "J Smith Building Ltd". Match the insured name to Companies House character for character.

Stopping at Companies House. Active status proves a company exists. It does not prove the director is not disqualified, or has not left three dissolved companies behind. Search the director as well as the firm.

Treating a pass as a verdict on the quote. The checks tell you who you are dealing with, not whether £42,000 is a fair price or whether the quote covers the job. That is a separate ten minutes, and it is the one that decides what the project costs.

Doing the checks after the deposit. All eight cost nothing. Do them before any money moves. Our complete guide to avoiding rogue traders lists the warning signs that should send you back to this list.