Choosing a builder is one of the few purchases most people make with almost no way to check the quality before they buy. You can’t test-drive a loft conversion. By the time you find out whether a builder was any good, you’re usually several thousand pounds and several weeks into the project. That’s exactly why it’s worth spending an hour asking the right questions before you commit, rather than finding out the answers the hard way.
1. Are You Insured, and Can I See Proof?
Public liability insurance isn’t optional, and it isn’t a formality — it’s what protects you if something goes wrong on your property during the build. Ask for the policy documents, not just a verbal assurance. Reputable builders will send them without hesitation. A figure worth asking about specifically: how much cover, and does it apply to the type of work you’re having done.
2. What Qualifications Do You and Your Team Actually Hold?
“Experienced” is not a qualification. Ask specifically about trade certifications (NVQ, City & Guilds), site safety certification (CSCS cards), and whether the person managing your project holds any chartered industry membership (MCIOB is the recognised standard for construction management). None of this guarantees good work on its own, but its absence is a real warning sign.
3. Is the Quote Fixed-Price or Estimated?
This is the single biggest source of disputes in the building trade. An “estimate” can move. A genuine fixed-price quote, itemised and agreed in writing before work starts, cannot — the price you sign is the price you pay, barring genuine changes you request yourself. Ask explicitly which one you’re being given, because the two words get used interchangeably by builders who don’t want to commit.
4. What’s Included, and What’s Excluded?
A cheap-looking quote that excludes skip hire, scaffolding, waste removal, or making good afterwards isn’t actually cheaper — it just moves the cost to an invoice you weren’t expecting. Ask for a full written breakdown of what’s in the price and what isn’t, and get it before you compare quotes against each other. Two quotes with a £5,000 gap between them often turn out to include completely different scopes of work.
5. Who Is Actually Managing My Project?
On larger jobs, ask whether one person is responsible for your project from start to finish, or whether you’ll be dealing with a rotating cast of subcontractors and site managers. A single point of contact matters more than most people expect — it’s usually the difference between a project that runs to plan and one where nobody quite knows what was agreed last week.
6. Can I See Real Examples of Similar Work?
Photos of a “similar” extension mean little without context. Ask for examples of work genuinely comparable to yours — same type of property, similar scale — and ideally an address or area you could look up. A builder confident in their work will show you, not just tell you.
7. What Happens If Something Goes Wrong After Completion?
Ask about the warranty in writing: how long it runs, and what it actually covers. A verbal “we’ll sort it” isn’t a warranty. A written 12-month (or longer) guarantee that specifies what’s covered is.
8. How Do You Handle Planning Permission and Building Regulations?
For anything beyond minor works, find out whether planning and Building Control management is included in the quote or billed separately, and who’s responsible if an application needs amending. This is a common place for costs to creep — and a common place for a project to stall if nobody’s managing it properly.
9. What’s a Realistic Timeline, Start to Finish?
Ask for a specific timeframe, not a vague “a few weeks.” A builder who’s done the job before should be able to give you a realistic start-to-finish estimate, including the time it takes to get planning sorted before work even begins.
10. Can I Speak to a Recent Customer?
Reviews online are useful, but a direct conversation with someone who had similar work done recently tells you more in five minutes than a star rating does. A builder with nothing to hide will happily put you in touch.
The Pattern Worth Noticing
None of these questions are unreasonable to ask, and a genuinely good builder won’t flinch at any of them. The ones worth avoiding are the ones who get evasive, rush you to sign, or can’t produce paperwork on request. That hesitation is usually the most useful answer you’ll get.
As a builder in Bath that’s MCIOB chartered, CSCS credentialed, and £10M+ insured, we’re used to being asked exactly these questions — and we’d rather you asked them before you booked than found out the answers afterwards. Arrange a free site visit and judge for yourself.
