Quick Answer
To hire a builder in the UK, get at least three written quotes, check for FMB membership or TrustMark registration, always use a written contract, and never pay more than 10–20% upfront. Verify references from completed projects before signing anything.
Hiring a builder is one of the biggest financial decisions you can make as a homeowner. Whether you're planning a loft conversion, a single-storey extension, a full renovation, or a new build, the builder you choose can make the difference between a dream project and a nightmare that costs twice the budget and takes twice as long. In 2026, the UK building industry is a mix of highly skilled professionals and a persistent minority of rogue traders.
This complete guide covers everything you need to know: the different types of builders, how to find and vet them, what a proper contract looks like, how payments should be staged, and the red flags that should stop you in your tracks.
In this guide
Types of Builders: Sole Trader, Small Firm, Main Contractor
Not all builders operate in the same way. Understanding the different types helps you choose the right fit for your project:
| Builder Type | Best For | Typical Day Rate |
|---|---|---|
| Sole trader | Small repairs, single room projects | £200–£350/day |
| Small building firm (2–10 staff) | Extensions, loft conversions, refurbs | £250–£450/day per person |
| Main contractor | Large builds, commercial-scale projects | Project price, often £50k+ |
| Specialist subcontractor | Specific trades within a larger build | Trade-specific rates |
For smaller projects (under £10,000), a well-reviewed sole trader can be excellent value. For larger projects, a small building firm provides more resilience — if one person is sick, the work doesn't stop. Main contractors typically manage subcontractors across larger builds and add a management fee, but handle everything under one contract.
FMB Membership and Other Professional Bodies
Unlike some trades, there is no legal requirement for builders to hold a specific licence. This makes professional body membership an important quality signal:
Federation of Master Builders (FMB)
The FMB is the UK's largest trade association for small and medium-sized building companies. FMB members are independently inspected, must carry adequate insurance, and comply with the FMB's code of practice. Crucially, FMB members have access to a free dispute resolution service — a valuable safety net for homeowners if disagreements arise during a project.
TrustMark
TrustMark is a government-endorsed quality scheme that covers builders and other trades. TrustMark-registered builders have undergone checks on their technical competence, customer service standards, and trading practices. They also have access to a consumer protection scheme.
Chartered Institute of Building (CIOB)
The CIOB is a professional body for construction management. MCIOB or FCIOB members are typically project managers or larger building firm owners who have demonstrated significant expertise and commitment to professional standards.
How to Get and Compare Quotes
For a full guide to the quotes process, read our article on how to get multiple quotes for home work in the UK. For building projects specifically:
- Prepare a detailed brief: The more specific your brief, the more comparable your quotes will be. Include drawings or sketches if possible, specify materials and finishes, and clarify what you expect the builder to supply vs what you will provide.
- Get at least three quotes: Building work quotes can vary by 30–50% for the same job. Three quotes gives you a realistic market price and helps identify outliers.
- Insist on itemised quotes: A single lump-sum figure is not sufficient. You need costs broken down by labour, materials, groundwork, waste disposal, and any specialist subcontract work.
- Ask each builder to visit the site: No reputable builder will provide a serious quote without seeing the job first. Be wary of phone or email quotes for any significant building work.
You can also post your building job on GetQuickHelp to receive quotes from vetted local builders. Describe your project in detail to get the most accurate responses.
Contracts: What to Include
A written contract is essential for any building project over a few hundred pounds. Our dedicated guide on whether you need a contract with a builder covers this in detail. At minimum, your contract should include:
- ✓ Full description of the work to be done
- ✓ Start date and estimated completion date
- ✓ Total price and payment schedule
- ✓ How changes (variations) will be handled and priced
- ✓ Who is responsible for obtaining planning permission or Building Regs approval
- ✓ Dispute resolution process
- ✓ Insurance details (public liability, employer's liability)
- ✓ What happens if either party wants to terminate
The FMB provides standard contract templates for members to use with clients. The JCT (Joint Contracts Tribunal) also publishes homeowner-friendly contracts suitable for smaller domestic projects.
Stages of Payment
Payment structure is one of the most important and contentious aspects of any building project. Here is the approach recommended by consumer organisations and the FMB:
| Stage | Typical Payment | Notes |
|---|---|---|
| Deposit (on signing contract) | 0–10% | Not always required for small jobs; max 10% is standard |
| Stage 1 complete (e.g. groundworks) | 20–25% | Pay on completion of agreed milestone |
| Stage 2 complete (e.g. walls up) | 20–25% | Inspect work before releasing payment |
| Stage 3 complete (e.g. weathertight) | 20–25% | Continue milestone-based releases |
| Practical completion | Remaining balance minus retention | Typically 95–97.5% total paid |
| Retention released | 2.5–5% | Released after agreed defects period (3–12 months) |
Red Flags When Hiring a Builder
Our full guide on red flags when hiring a tradesperson is worth reading in full. For builders specifically:
- ✕Demands more than 10% upfront on a large project. If a builder says they need 30–50% before starting, this is a major warning sign. It suggests cash flow problems or an intention not to return.
- ✕Can't provide references from similar completed projects. Any builder who has been operating for more than a year should be able to point you to completed work you can inspect.
- ✕Refuses to put the quote in writing. A verbal quote is not a quote. It's a conversation.
- ✕Pressure to start immediately or offers a "special price this week." Reputable builders have busy schedules and don't need to use sales pressure.
- ✕No insurance or can't produce the certificate. Public liability and employer's liability insurance are essential. Ask for certificates and check they are current.
Also read our guide on 10 questions to ask before hiring any tradesperson for a broader checklist.
Frequently Asked Questions
Do I need planning permission before hiring a builder?+
Some projects (extensions over certain sizes, loft conversions, change of use) require planning permission before work starts. Your builder can advise, but ultimately it's the homeowner's responsibility. Many extensions fall under Permitted Development rights, but always check with your local planning authority first.
What insurance should a builder have?+
At minimum: public liability insurance (minimum £1m, ideally £2m or £5m for larger projects) and employer's liability insurance (legal requirement if they employ anyone). For larger projects, contract works insurance (protecting the build itself) is also important.
Can I supply my own materials to save money?+
Yes — many homeowners buy their own bathroom suites, kitchen units, or tiles to save money. However, if you supply materials, you take on some of the liability if they are faulty. Discuss this arrangement clearly in your contract and ensure the builder is aware of lead times.
What is the FMB and how do I find a member?+
The Federation of Master Builders is the UK's largest building trade body. You can find FMB members at fmb.org.uk. Members are independently inspected and must comply with the FMB Code of Practice.
How long does a typical extension take?+
A single-storey rear extension (25–35 sq m) typically takes 10–16 weeks from start of building work. Add planning permission time (8 weeks minimum) and pre-build lead time (4–8 weeks). A double-storey extension can take 16–24 weeks on site.
What happens if my builder abandons the project?+
If your builder walks off the job, your first step is to write to them formally requesting they return and complete the work. If they don't respond, you can claim the cost of completing the work from another builder in the small claims court (up to £10,000 in England). FMB members also have access to a dispute resolution service.
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