Homeowner guide · UK

How to spot a cowboy builder before you sign

UK homeowners lose an estimated £3.5 billion a year to rogue traders, according to figures cited by the Chartered Trading Standards Institute. There is no licensing scheme for general builders in England or Wales — anyone with a van and a website can call themselves one.

None of the signs below is damning on its own. Treat three of them as a reason to pause; five as a reason to walk.

The price was never written down

If the only number you've been given came over the phone or scribbled on a notepad, you don't have a quote — you have a guess. Reputable builders put figures in writing because they expect to be held to them.

They want a huge slice of money before lifting a finger

A modest deposit covering early materials is normal, typically somewhere around 10–15% of the job. Anything closer to a third or a half of the total, paid before any work has happened, is the classic shape of a job that's about to go wrong.

Cash in hand, no paperwork in return

There's nothing illegal about settling in cash. There is something very wrong with refusing to issue any invoice or receipt for it. Without a paper trail you cannot prove what was paid, what was promised, or that the transaction even took place.

You can't actually find them anywhere

A working mobile and a Gmail address aren't a business — they're a way to disappear. A real builder has somewhere you could send a letter to, even if that's their home. If you can't pin them to a location, you can't pin them to anything.

Insurance? They'll dig it out later

Public liability cover (around £2m as a floor) is the bare minimum. If they have anyone working alongside them, employers' liability is a legal requirement. A professional brings paperwork to the first meeting; a chancer puts the question off forever.

There's always a reason you have to decide today

The price is only good until tonight. Another job starts on Monday. The slot will go. These are sales tactics, not scheduling realities — and they exist purely to stop you taking the time you'd otherwise use to check them out.

Past customers? It's complicated

Time in the trade is not a reference. Names and numbers of homeowners whose jobs you can actually phone up about are. When those references never quite materialise — or the contacts never quite answer — you're not dealing with a track record.

One line, one number, no detail

A quote that says 'Extension — £55,000' tells you nothing useful. You can't compare it, you can't dispute it, and you can't tell what's been left out of it. Costs should be split across labour, materials, fittings and any provisional sums.

No timeline anyone is willing to commit to

'Should be done in a couple of months' is not a programme of works. Start dates, key milestones and target completion belong on paper. Without them, the job can drift indefinitely while you have no real basis to challenge the slippage.

The company on the van isn't the company on Companies House

If they're trading as a limited company, that company should be live, up to date with its filings, and registered to the people you're meeting. A name that doesn't appear, or shows up dissolved, or is owned by a stranger, is a serious problem.

They turned up at your door

The neighbour's roof story, the spare tarmac, the loose tile they noticed walking past — doorstep approaches sit behind a huge share of rogue trader complaints. The right response is always the same: take a card, do not commit to anything in person.

Not a single accreditation to their name

Memberships aren't legally required, and a logo on a website doesn't prove much by itself. But a builder with no link to FMB, TrustMark, NICEIC, NAPIT, NFRC or any other recognised body has chosen to operate entirely outside any external standard.

The price is suspiciously low

If one quote sits a long way below the others, it's rarely a bargain. It's usually either bait — to be made up later through 'unforeseen' extras — or a sign that whoever wrote it is planning to cut something significant out of the job to make the numbers work.

They wave away building regulations

Structural alterations, layout changes and most extension work need Building Control sign-off. A builder who treats that as an inconvenience, or promises to 'sort it later', is happy to leave you with work that's hard to insure, hard to sell and sometimes unlawful.

The scope keeps growing once you're committed

Genuine surprises come up on real jobs. What separates them from a pattern is timing and frequency. If price rises start landing as soon as deposits are paid, and keep landing every few weeks, the scope creep is doing what it's designed to do.

Accreditations that matter

Memberships worth checking

Not all accreditations are equal. These carry genuine weight in the UK.

FMB

Federation of Master Builders

The largest UK builder trade association. Members go through independent checks and sign up to a code of practice; warranty cover is available through MasterBond.

TrustMark

The government-backed quality scheme covering work in and around the home. Required for most state-supported energy efficiency schemes.

NICEIC / NAPIT

Electrical competent person schemes

Allow registered electricians to self-certify notifiable work — anything in bathrooms, kitchens, new circuits or consumer units.

Gas Safe

Gas Safe Register

Not optional. Anyone touching gas pipework, boilers or appliances must be on the register; working without it is a criminal offence.

NFRC

National Federation of Roofing Contractors

Vets roofing firms on technical competence, health & safety and financial standing — a meaningful filter in a trade homeowners struggle to inspect themselves.

Don't trust your gut alone — check them.

Search My Builder runs hundreds of automated checks against Companies House, trade body directories, review platforms, regulatory registers and more. If a builder has a track record worth worrying about, it's usually findable in minutes.

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Background figures (£3.5bn annual cost, lack of mandatory licensing in England & Wales) are widely reported by the Chartered Trading Standards Institute and the Federation of Master Builders. For a longer homeowner-side write-up of the same topic, see MyBuildAlly's guide to avoiding cowboy builders.

This page is general consumer guidance about how to assess any UK builder. It is not directed at, and does not refer to, any specific person or company. Nothing here is legal advice. See our full disclaimer.