The 10-step vetting checklist
Run all 10 checks before signing any contract over £20,000. Step 1: Companies House search — confirm 3+ years trading, no overdue accounts, no CCJs. Step 2: insurance verification — public liability £2m+, employer's liability £10m+, professional indemnity £1m if design provided. Step 3: TrustMark or FMB accreditation — verify directly on each body's website. Step 4: three reference addresses inspected in person, with homeowner phone conversations. Step 5: online reviews on Google, Trustpilot, Checkatrade — look for response patterns to complaints. Step 6: trade certifications — NICEIC, NAPIT, Gas Safe, FENSA. Step 7: audited accounts for projects over £75k. Step 8: VAT registration confirmed at HMRC. Step 9: directors' disqualification check. Step 10: insurance-backed warranty available for 6 years.
Companies House — what to look for
Free at companieshouse.gov.uk, takes 5–10 minutes per company. Key checks: incorporation date (3+ years trading shows stability); annual accounts filed and not overdue (overdue is a red flag); no county court judgments; net assets positive (avoid companies with consistent net liabilities); no recent name change (phoenix companies are common in distressed construction); directors with no other failed companies; no insolvency events in company history. Pay particular attention to companies that have changed name in the last 24 months or where directors have multiple recent insolvencies — these are common patterns for serial undercapitalised contractors.
Insurance verification — do it directly
Don't accept insurance certificates at face value. Three direct-verification steps. First, contact the insurer named on the certificate using a phone number from the insurer's own website (not from the certificate, which can be faked). Second, ask the insurer to confirm: policy number, named insured exactly matching the company name, policy active and not lapsed, premium paid up to date, level of cover. Third, verify the works you're commissioning fall within the policy scope — some PL policies exclude high-risk works like structural alterations or working at height. Builderr provides direct insurer contact details and consent to verify on every quote.
Reference inspection — the in-person test
Three reference addresses of comparable projects completed in the last 12–18 months. Visit at least two in person. Drive past first — observe exterior finish quality, kerb appeal, integration of new work with existing fabric. Then knock and request 5 minutes with the homeowner. Three questions to ask: (1) was the project completed on the agreed date and budget; (2) were snags resolved promptly and to your satisfaction; (3) would you hire the same contractor again. Watch body language as much as words — hesitation or qualified positives are warning signs. Also ask to see the work inside if convenient — workmanship in non-visible areas tells you the most.
What to do when something fails the vetting
Any single major failure (e.g. no insurance certificate, no Companies House record, refused references) is grounds to walk away. Multiple minor failures (e.g. accreditation expired, one bad review, late response to documentation requests) require deeper investigation. Don't accept oral explanations — request written answers. Compare the failed contractor with two others using the same checklist. The best contractors pass all 10 checks cleanly within 5 working days. Builders who require chasing for basic documentation are signalling how they'll behave during the project, when delays compound and pressure mounts. Always have two alternative contractors as back-up before terminating engagement with a preferred choice.
