Quick Answer
Finding a reliable builder is the single most important decision in any building project. A bad builder can turn a straightforward extension into a nightmare of delays, cost overruns, and substandard work.Start With RecommendationsThe best builders rarely advertise — they are b...
Key Information
- Last Updated:
- 6 Jun 2026
- Category:
- Building Advice
- Reading Time:
- 1 min read
Finding a reliable builder is the single most important decision in any building project. A bad builder can turn a straightforward extension into a nightmare of delays, cost overruns, and substandard work.
Start With Recommendations
The best builders rarely advertise — they are booked months ahead on word of mouth. Ask neighbours with recent extensions, check local Facebook groups, and ask your architect or structural engineer.
Essential Checks
Every builder should have: public liability insurance (minimum £5 million for structural work), employers liability insurance, a registered business address, and a VAT number if their turnover exceeds the threshold.
Getting Quotes Right
Provide identical specifications to every builder quoting. A proper quote should be itemised with labour, materials, and provisional sums for unknowns.
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I'm excited to start my extension, but it's daunting choosing a builder! I've heard horror stories about delays. Any tips on checking their insurance policies?
Don't forget to ask for proof of insurance. It's not uncommon for builders to overlook this, and you don't want to be left footing the bill for damages.
I've just started planning our extension. Any tips on how to spot fake VAT numbers?
I understand the importance of checking insurances and registrations, but could you clarify what you mean by 'a registered business address'? What does that entail?
Also check if they're registered with a competent persons scheme, such as CHAS or Safecontractor. It's another sign of professionalism and commitment to safety.
I appreciate your thorough checklist, but could you clarify what constitutes a 'straightforward' extension? Every project seems unique!
I've just started planning my loft conversion. Any tips on how to ask neighbours for builder recommendations without sounding too nosey? 😊
While I agree asking around is crucial, I'm curious about why you don't advise checking online reviews and ratings platforms? Some people might not be comfortable sharing their experiences on local groups.
Regarding insurance, wouldn't £1 million be sufficient for smaller projects? Or is £5 million really necessary?
I appreciate the thoroughness of this checklist. However, could you elaborate more on what 'provisional sums for unknowns' entails? That's not quite clear to me.
Don't forget to check if their insurance covers your specific project. For instance, some policies exclude certain trades or types of work.
Don't forget to ask for their Construction Skills Certification Scheme (CSCS) cards. It's not a legal requirement but it's a good indicator they're properly trained.
I recently used this checklist to find a builder for my kitchen extension in Manchester. It really helped me weed out the cowboys!
Hi there! Just starting my own extension project. Any tips on what questions to ask neighbours about their builders? Thanks!
I appreciate your thorough checklist, but could you clarify what constitutes 'substandard work'? I want to ensure I spot any issues before it's too late.
I recently used this checklist to find a builder for my kitchen extension in Bristol. Saved me from potential headaches!