How to find a builder you can trust

Choosing a builder is a decision that shapes an entire project's budget, timeline and stress level, and the checks worth doing upfront are largely the same regardless of whether the job is a small refurbishment or a full extension.

Trade body membership is a useful starting filter, but it's worth understanding what each one actually checks. FMB, the Federation of Master Builders, vets its members on company history, financial records and proof of insurance before admitting them, and independently inspects a sample of member work on site rather than relying purely on paperwork. TrustMark is the government-endorsed quality scheme, and registered firms are similarly vetted, independently inspected, and bound to a formal code of conduct. Neither membership should be taken on trust from a builder's word alone, since firms have occasionally been found to falsely claim membership; both FMB and TrustMark maintain public registers, and checking a firm's name or membership number directly on the relevant register takes a couple of minutes and confirms whether the claim is genuine.

Getting multiple quotes is worth doing properly rather than as a box-ticking exercise. Three quotes for a similar scope of work is a reasonable minimum, and it's worth asking each builder to quote against the same written specification rather than their own interpretation of a verbal brief, since otherwise the quotes aren't genuinely comparable. A confident, established builder will happily provide contact details for three to five recent customers; actually calling them, and asking specifically whether the job finished on time, whether unexpected costs came up along the way, and whether they'd use the builder again, tells you considerably more than a handful of five-star reviews on a profile page.

Review platforms such as Checkatrade and MyBuilder are a useful second layer of verification, since they collect customer reviews tied to a verified trade profile. It's worth reading a builder's full review history rather than just the headline star rating, looking specifically for any pattern of complaints about missed deadlines, communication, or unexpected charges, since one or two mixed reviews among many strong ones is normal, but a repeated specific complaint is a signal worth taking seriously.

Insurance is a check that's easy to skip and genuinely important not to. Public liability insurance of at least £2 million is a reasonable minimum to confirm for a domestic project, rising to £5-10 million for a larger or more complex job; ask to see the policy or certificate directly rather than simply taking a builder's word that they're covered. A builder without proper insurance leaves you personally exposed if something goes wrong on site, whether that's damage to your property or a neighbour's, or an injury to someone working on the job.

A written contract, agreed before any work starts, is the single most protective document in the whole process. It should set out the exact scope of work, the materials and specification being used, a realistic timescale, and a schedule of staged payments tied to specific milestones rather than a calendar date. A reasonable deposit is commonly 5-10% of the contract price; anything from around 25% upward is generally treated as a serious warning sign, and a demand for 50% or more before any work has started isn't really a deposit at all, it's most of the job's value handed over with almost nothing yet delivered.

A handful of warning signs are worth taking seriously if they come up during the quoting or early contract stage: reluctance to provide a written contract or itemised quote, no verifiable insurance, pressure to pay a large amount in cash with no invoice, an inability or unwillingness to provide references, and a quote that seems considerably cheaper than every other one you've received without an obvious reason why. None of these individually proves a builder is a rogue trader, but together they're the pattern that most commonly precedes a disputed, unfinished or badly executed job, and they're worth walking away from rather than talking yourself past.

Asking to see a current job in progress, rather than only finished photographs, is one of the more revealing checks available and costs nothing but a short visit. A tidy, safely run site, with materials stored sensibly and basic site safety visibly in place, says something about how a builder operates day to day that a finished-project photo can't. It's also worth asking directly who will actually be on site day to day, since some firms subcontract most of the physical work while the person you met at quoting stage manages several jobs at once; that's not unusual and isn't automatically a problem, but knowing it in advance, and confirming who to contact if something needs addressing mid-project, avoids confusion once work is under way.

Frequently asked questions