Compare Builders: How to Spot a Rogue Trader in 2026 (UK)
Rogue traders cost UK homeowners hundreds of millions a year. Almost every case shares the same seven warning signs: no written quote, cash-only or large upfront deposits, no verifiable address, pressure to decide today, a company too new to check, no insurance you can confirm, and reviews you cannot trace to a real job. This guide shows exactly how to check each one before you sign.
The 7 rogue-trader red flags
- 1. No written, itemised quote. A legitimate builder gives a fixed written quote broken down by labour, materials and provisional sums. A verbal ballpark or a figure scribbled on the back of a card is the single biggest warning sign.
- 2. Cash-only or a large upfront deposit. Deposits above 25% of the job value, or demands for cash to avoid VAT, are red flags. Pay by card or bank transfer so you have recourse.
- 3. No verifiable trading address. A mobile number and nothing else means you cannot find them after the job. Insist on a registered address and cross-check it.
- 4. Pressure to decide today. Real builders are booked weeks out. Doorstep offers and one-day-only discounts are designed to stop you checking them.
- 5. A company too new to check. Search Companies House for the incorporation date and any string of dissolved companies at the same address — a common phoenix-company pattern.
- 6. Insurance you cannot confirm. Ask for public liability and, where staff are used, employer’s liability certificates — then phone the insurer to confirm the policy is live.
- 7. Reviews you cannot trace. Genuine reviews name a real job and place. Be wary of a wall of five-star reviews all posted the same week with no detail.
How to verify a builder in 10 minutes
- Companies House: confirm the company exists, its age, and its filing history.
- Trade bodies: check FMB, CIOB, TrustMark or the relevant competent-person scheme register directly on their site — not a logo on a flyer.
- Insurance: get the policy number and call the insurer.
- References: ask for two recent jobs in your area and actually call them.
- Contract: use a JCT HomeOwner or FMB contract with a payment schedule tied to stages, not dates.
If it has already gone wrong
Stop further payments, put everything in writing, and keep photos and receipts. Paying by credit card for anything over £100 gives you Section 75 protection. Report rogue traders to Citizens Advice consumer service, which shares data with Trading Standards. Escalate structural or safety defects to your local Building Control.
The official registers worth checking — and what each proves
A logo on a van or flyer proves nothing; check the source register directly. Each of these tells you something different:
- Companies House — confirms the company exists, its incorporation date and directors, and flags a trail of dissolved companies at one address (the classic phoenix pattern).
- Gas Safe Register — the legal requirement for anyone working on gas appliances or pipework; check the engineer’s ID number, not just the company.
- A Part P competent-person scheme (such as NICEIC or NAPIT) — lets an electrician self-certify notifiable electrical work instead of a separate Building Control application.
- MCS — required if the job includes heat pumps or solar and you want it to qualify for grant funding such as the Boiler Upgrade Scheme.
- TrustMark — the government-endorsed quality scheme that vets trading standards, technical competence and customer service.
- FMB or CIOB — membership that requires independent inspection and offers contract and dispute-resolution support.
Run the same builder through two or three of these, cross-check the address, and confirm any insurance policy by phoning the insurer. Before you sign, read every line of the quote itself — our guide on how to read a builder’s quote shows the wording that separates a firm price from a moving target, and how to lock in a fixed-price quote keeps the final bill from creeping.
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