JCT Contracts Explained: What Homeowners Need to Know Before Signing
A surprising number of extensions and renovations proceed on nothing more than an accepted quote and a handshake. That works fine right up until there's a dispute about a delay, a defect, or a payment — at which point the absence of a proper contract becomes very expensive to discover.
Why a quote isn't enough
A quote sets out a price. It rarely sets out what happens if the start date slips, who's responsible for insuring the works, how variations get priced and agreed, what happens if the builder becomes insolvent partway through, or what recourse you have if the finished work has defects. A proper contract covers all of it, agreed before work starts rather than argued about afterwards.
What JCT is
JCT (Joint Contracts Tribunal) publishes standard-form construction contracts used across the industry, including versions specifically designed for homeowners: the JCT Homeowner Contract (with or without a consultant administering it) is written for exactly this kind of domestic extension or renovation project, in plainer language than the commercial versions.
What it actually covers
- Scope and specification, referencing the drawings and specification so there's no ambiguity about what's included
- Price and payment schedule, tied to stages of work rather than arbitrary dates, so you're not asked to pay ahead of progress
- Timescale and what happens if it slips, including extension-of-time provisions for genuinely unforeseen delays versus the builder simply running late
- Variations, requiring extra costs to be priced and agreed in writing before they're carried out, not added to the final invoice
- Insurance responsibility, making clear who insures the works while they're underway — an easy gap to miss on a homeowner's own buildings insurance
- Defects liability, typically a defined period after completion during which the builder must return and fix genuine defects at their own cost
- Dispute resolution, setting out a process before things escalate to solicitors
With or without a consultant
The Homeowner Contract comes in two versions: one where an architect or contract administrator formally certifies payment stages and completion, and a simpler version without one, where the homeowner administers it directly. Where an architect is already involved for design, using them as contract administrator too is often the more straightforward route, though it's a separately scoped service worth clarifying in advance.
What happens without one
Without a written contract, disagreements default to whatever can be reconstructed from emails, texts and memory — a slow, expensive and uncertain way to resolve a dispute about, say, whether a delay was the builder's fault or caused by a late decision on your side. A proper contract doesn't prevent every disagreement, but it gives both sides a clear, agreed process for resolving one.
Where this fits into the wider project
Getting a proper contract in place is one of the most valuable hours spent before a builder starts on site, and one of the most commonly skipped — usually because momentum is high and nobody wants to be the one raising it. Reviewing the contract terms alongside the quotation, before either is signed, is a standard part of protecting a project from day one rather than only reacting once something's gone wrong.