Most building disputes are really contract disputes: the job went wrong at the point where nobody wrote down what was agreed. A proper contract costs £40 and an hour of reading; the average dispute costs thousands and months. This pillar guide maps everything the paperwork side of a project involves — what to sign, what to pay and when, and how changes and delays should be handled — with links to the detailed guides in this series.
The contract itself
For renovation and extension work the standard forms are published by the JCT (Joint Contracts Tribunal). Two matter to homeowners: the JCT Home Owner Contract (small jobs, plain English, two versions depending on whether a consultant is overseeing the work) and the JCT Minor Works Building Contract (larger projects, typically used up to around £250,000). Our guide to builder contracts and JCT forms covers the clauses in detail.
Whatever form you use, the contract should pin down six things:
| Element | What it fixes |
|---|---|
| Scope | Drawings + specification listed as contract documents |
| Price | The contract sum, and what is provisional |
| Programme | Start date, completion date, extension rules |
| Payments | Stage schedule or monthly valuations |
| Changes | How variations are priced and authorised |
| Ending | Defects period, termination grounds, disputes |
A quote on headed paper is not a contract — though it can become legally binding once accepted, which is why the wording matters. If the builder “doesn’t do contracts”, treat that as the first red flag in our vetting checklist.
Money: deposits, stages, retention
Three rules protect almost all of your cash exposure:
- Deposit small or none. On medium and large jobs a reputable contractor funds the first weeks from working capital; materials-heavy trades (kitchens, windows) legitimately ask for more. Anything above 10–25% deserves scrutiny.
- Pay in arrears, against work done. Staged payments should follow completed milestones — never the calendar. You should always owe the builder slightly less than the value of work on site, not more.
- Hold a retention. Keeping 2.5–5% until snagging is complete is standard practice; our guide to snagging lists and retention explains how to run the end of the job.
Benchmark the numbers themselves — trade day rates and typical package costs — against the UK Renovation Cost Index and our tradesperson day rates guide before you sign anything.
Changes and delays
Variations are where tidy budgets die. The discipline is simple: no instruction without a price — every change agreed in writing (email is fine) with its cost and time effect before the work is done. Projects that skip this end the job arguing about a stack of undocumented extras.
Delay works the same way in reverse. The contract should state the completion date, the grounds on which the builder gets more time (weather, your late decisions, genuinely unforeseen work), and ideally liquidated damages — a fixed weekly figure you can deduct if the job overruns without excuse. JCT forms have these mechanisms built in.
Your legal safety nets
Even without a written contract, the law implies terms into every building job: work done with reasonable care and skill, at a reasonable price, in a reasonable time (Consumer Rights Act 2015). If you signed the deal at your kitchen table rather than the builder’s premises, you normally also have a 14-day cooling-off period — and if the builder never told you about it, that window can stretch to 12 months. The wider legal framework — negligence, the Defective Premises Act, limitation periods — is mapped in our construction law pillar.
When it goes wrong anyway
A good contract doesn’t prevent disputes; it makes them winnable. Escalation runs: polite written complaint → formal letter → mediation or adjudication → court as the last resort. The full route map, including when you can lawfully withhold payment, is in our builder disputes pillar.
In this series
Detailed guides in this cluster cover: JCT Home Owner contracts, what to include in a builder contract, whether quotes are legally binding, deposits, staged payments, managing variations, cancellation and cooling-off rights, insurance-backed guarantees, and delay damages. New guides publish through the coming weeks — this page links each one as it goes live.
This guide is general information for homeowners in England and Wales, not legal advice on a specific dispute.
