Do I need a contract with my builder? A UK guide

Strictly, no. Sensibly, yes. Problems with building work are common (Citizens Advice (opens in a new tab) found in July 2026 that 1 in 4 homeowners had a problem with their most recent repair job), and many of the disputes that follow trace back to the same root cause: nobody wrote down what was agreed. This guide covers what the law actually requires, why verbal agreements go wrong, what a written contract must include, what the JCT Minor Works contract does in plain English, and where milestone escrow fits alongside all of it.

Is a written contract legally required for building work?

No. There is no UK law requiring a written contract for domestic building work, and a verbal agreement with your builder is legally binding. The moment you agree a scope and a price, you have a contract, signed or not.

You also have some protection either way. The Consumer Rights Act 2015 implies terms into every contract between a consumer and a trader: the work must be carried out with reasonable care and skill, within a reasonable time if no deadline was agreed, and for a reasonable price if no price was fixed.

So the question is not whether you have a contract. You do. The question is whether you can prove what is in it. That is the entire case for writing it down. The same goes for the money: once the stage payment schedule is in the contract, you can ask your builder to use milestone-based payment protection, so each stage is funded before it starts and released when you approve it.

Why verbal agreements fail

Verbal agreements fail because, months into a build, you and your builder will genuinely remember different deals, and neither of you can prove yours. It is rarely dishonesty. Projects evolve, conversations happen over the noise of an angle grinder, and small decisions pile up: was the outside tap included, did the price cover tiling or just tiling labour, who agreed to move the soil pipe?

Each of those gaps is small. Together they harden into a dispute, and renovation disputes are brutal. If one ends up as a small claim in the county court, the median wait for a trial is 41 weeks (Ministry of Justice, Civil Justice Statistics, April to June 2026). In court, a verbal contract becomes one person's word against another's, which is an expensive coin toss. A written contract does not stop disagreements, but it turns most of them into a two-minute check of the document rather than a stand-off.

What a written building contract must include

At minimum, a building contract needs to pin down six things: scope, price, a payment schedule, a variations procedure, dates, and a route for disputes.

• Scope of works. An itemised description of exactly what is being built, referencing drawings and specifications where they exist. List what is excluded too: exclusions cause as many arguments as inclusions.
• Price and payment schedule. The total, and precisely when each instalment falls due. Tie every payment to a completed, checkable stage of work rather than a calendar date. Our free stage planner builds a stage schedule you can attach to the contract.
• Variations. A rule that any change to the scope is priced in writing and agreed by both of you before the extra work starts. This single clause prevents the classic end-of-project invoice shock.
• Dates. Start date, estimated completion, and what happens if the job overruns.
• Disputes. The steps you both agree to take before anyone calls a solicitor: a written notice, a meeting, then mediation or an independent expert opinion.
• The practical extras. The builder's public liability insurance details, who obtains Building Regulations approval, who pays for skips and scaffolding, and whether VAT is included.

JCT Minor Works in plain English

The JCT Minor Works Building Contract is a standard form contract for smaller building projects, published by the Joint Contracts Tribunal, the body that has produced the construction industry's standard contracts since 1931. Rather than drafting terms from scratch, you adopt a tested set of rules the industry already understands.

In plain English, it does four things. It has a named contract administrator, usually your architect or surveyor, who certifies what work is complete and what payment is due. It sets out how variations are valued, so changes have a price mechanism instead of an argument. It defines practical completion, the formal point at which the job is done apart from minor items. And it includes a rectification period after completion, during which the builder must return and fix defects.

It is designed for projects with a professional administering the contract, so it can be more than a bathroom refit needs. For homeowner-run projects, JCT publishes a separate Building Contract for a Home Owner/Occupier written in plainer language, and RIBA offers a comparable domestic contract. Either costs tens of pounds, which is the cheapest insurance in construction.

If an architect or designer is administering your contract, ask them about the Renopay partner programme for architects and designers.

Where milestone escrow fits alongside a contract

A contract records what was agreed; it does not hold the money or move it. Even a perfect contract cannot stop you paying ahead of the work, cannot make payment arrive as soon as a stage is finished, and cannot enforce itself: if the other side ignores it, your remedy is court.

Milestone escrow adds the missing half. Each stage's money is paid in and held securely before that stage begins, and released when the stage is signed off. The builder is paid for completed work, and the payout is released as soon as the stage is approved. Platforms like Renopay work this way, so neither side can touch the money until the work is signed off. Client funds are held by OPP, an FCA-authorised electronic money institution.

Escrow is not a replacement for the contract. It does not define your scope, set quality standards or deal with variations: the contract does that. The pairing is the point. The contract sets the rules of the project, and escrow makes the payment side of those rules actually happen. For the wider picture, see our guide to paying a builder safely.

Get the agreement in writing, then make the money follow it. Ask your builder to set it up on Renopay to run your project on a funded milestone schedule alongside your contract.

Frequently asked questions

Is a verbal agreement with a builder legally binding in the UK?

Yes. A verbal agreement is a binding contract, and the Consumer Rights Act 2015 still requires the work to be done with reasonable care and skill. The problem is proof: if you disagree about what was included, neither side can show what was agreed, which makes disputes slow and expensive.

Is a builder’s quote legally binding?

A quote is a fixed price for the work it describes, and once you accept it, it becomes part of your contract, so the builder normally can’t charge more for the same work. An estimate is only a best guess and can change. If no price was agreed at all, the Consumer Rights Act 2015 says you pay a reasonable price. Extra work is a variation, and should be priced and agreed in writing before it is done.

What should a building contract include in the UK?

Six essentials: a detailed scope of works, the price, a stage-based payment schedule, a written variations procedure, start and completion dates, and an agreed dispute process. Add the builder’s insurance details and who is responsible for Building Regulations approval.

What is the JCT Minor Works contract?

A standard form building contract published by the Joint Contracts Tribunal for smaller projects, administered by an architect or surveyor who certifies work and payments. For projects without a professional administrator, JCT’s Building Contract for a Home Owner/Occupier is the simpler domestic version.

This article is general information about contracts for building work in the UK, not legal advice. For advice on a specific situation, speak to a solicitor. Renopay is a technology platform. Payment services are provided by Online Payment Platform Limited (OPP), an Authorised Electronic Money Institution regulated by the Financial Conduct Authority (FCA), Firm Reference Number 1003976. Client funds are held by OPP.