4 Things to Check Before You Choose a Contractor

You've had three quotes, you liked the person who came round, and you're ready to say yes. This is exactly the point where most bad hires happen — not because the work turns out badly, but because the checks that would have caught it never got done. They take an evening, not a weekend, and none of them cost anything.

These four aren't a full vetting process — see our guide on how to check if a builder is legit for the complete version, including Gas Safe and public liability cover. This is the short list: the four things that, done properly, catch almost everything that goes wrong.

1. Check Companies House — and match the names to the people in front of you

Companies House is free, takes two minutes, and most homeowners never open it.

Search the company name at find-and-update.company-information.service.gov.uk and check three things:

• Status is "Active". Not "Dissolved", not "Liquidation", not "Strike-off action in progress" — any of those and you're dealing with a company that is legally on its way out, whatever the person in your kitchen is telling you.
• The directors match who you're actually talking to. The "people with significant control" tab lists the real directors by name. If the person quoting and signing isn't one of them, ask why — sometimes it's a perfectly normal employee or project manager, but you want that explained, not discovered later.
• How long the company has actually existed. Compare the incorporation date against how long they've told you they've been trading. A company incorporated eight months ago claiming "20 years' experience" usually means a previous company was dissolved and a new one started — sometimes for an innocent reason, sometimes because the old one owed people money and "phoenixed" into a fresh entity with no debts and no bad reviews attached. Companies House shows you the filing history, so a pattern of short-lived companies with the same director's name is visible if you look.

None of this proves the work will be good. It proves the entity you're about to pay actually exists, is legally allowed to trade, and is run by the people you think it's run by.

2. Speak to two previous clients — in person, at the property

A testimonial page tells you what a builder chose to publish. A phone call tells you what someone is willing to say with the builder listening on the other end, metaphorically. Neither is worth as much as standing in a previous client's kitchen with the builder nowhere in the room.

Ask for contact details for two recent jobs — ideally one finished a few months ago (so any snagging has had time to surface) and, if possible, one still in progress or recently completed, so you can see standards on a live site rather than a tidied-up result. Arrange the visit directly with the homeowner, not through the builder, and go without them there if you can.

Once you're there, the questions that actually tell you something:

• "What went wrong, and how was it handled?" Something always goes wrong on a building project — a delivery delay, a measurement error, an unexpected finding once a wall's opened up. The answer you want isn't "nothing" — it's a specific problem and a builder who owned it without an argument.
• "Did the final price match the quote?" Some variation is normal and honest, especially where the quote flagged uncertainty upfront. A finished bill that's 40% over the quote, with no clear explanation, is not.
• "Would you use them again, and did they come back for snagging?" A builder happy to return weeks or months later to fix small defects is a different proposition from one who stopped answering the phone once the final invoice was paid.

If a builder is reluctant to give you two addresses, or only offers written testimonials, treat that as information in itself.

3. Never pay more than a 5–10% deposit

An established builder has a trade account with their merchants. They don't need your money before they can order a delivery of blocks, so a demand for a large upfront payment — a third, a half, occasionally the lot "for materials" — isn't a request for cash flow. It's a request to move most of your leverage to their side of the table before a single brick has moved.

A deposit in the 5–10% range is normal and reasonable. Beyond that, the rest of the payment schedule should follow completed stages of work, not the calendar — a percentage on foundations complete and inspected, another at wall-plate or roof watertight, another at first fix, and a final retention (commonly 5%) held back and released only once any snagging list is cleared. Our guide on structuring stage payments safely goes through the full schedule and what to write into a contract.

Watch for pressure specifically around the deposit: "I can only hold the start date if you pay this week", or a request for cash rather than a bank transfer with a paper trail. Either one is worth pausing on.

4. Check trade qualifications — and ask where the electrician is registered

A logo on a van or letterhead proves nothing on its own; a membership number that checks out on the actual register does. For general building work, look for Federation of Master Builders (FMB) membership or TrustMark registration, and verify the member number directly through findabuilder.fmb.org.uk or the TrustMark register rather than taking the certificate on the wall at face value.

Electrical work needs its own, separate check. A general builder may sub-contract the electrics — which is completely normal — but you need the electrician's registration, not the main contractor's. Ask by name which scheme they're registered with (typically NICEIC or NAPIT) and their registration number, then verify it yourself on the Electrical Competent Person Register. This matters beyond workmanship: notifiable electrical work under Part P has to be certified by a registered scheme member or signed off through building control, and a missing certificate is a real problem when you come to sell — it's one of the questions a buyer's solicitor asks. For a closer look at what a quote should and shouldn't include, our builder quote red flags guide covers the paperwork gaps that tend to travel together.

Do all four before you compare a single price

In order: Companies House confirms the business is real, active, and run by who you think. A face-to-face visit to a previous job confirms the standard of work and how problems get handled. A capped deposit keeps your leverage where it belongs until work is actually done. And verified qualifications — FMB or equivalent for the build, NICEIC or NAPIT for the electrics — confirm the people doing the work are certified to do it.

Each check takes minutes. Skipping any one of them is how homeowners end up mid-project with a company that's dissolved, a "reference" that was never independent, half the job's money gone before a wall's up, or electrical work with no certificate to show a buyer three years from now.

If you'd like a second opinion before you sign anything — on a quote, a contract, or a company that doesn't quite add up — a 30-minute consultation with one of our building consultants costs £59 and often saves a great deal more. Book a consultation, or run a quote through our free builder quote checker first.