A written contract is what turns a quote and a handshake into an enforceable agreement, and its main job on a domestic project is to set out when money changes hands and what triggers each payment.
Done properly, payments follow measurable progress on site — a stage completed, an inspection passed — rather than simply following dates on a calendar, which protects both sides if the programme runs long or short.
Fixing scope, price and programme in writing
Before payment stages mean anything, the contract needs to nail down exactly what is being built, for what price, and over roughly what timeframe. This is usually the accepted quote and specification attached as schedules to a short contract document, rather than a separate description written from scratch.
Where the contract and the quote disagree on any point, that discrepancy needs resolving before signing — it is far cheaper to query it now than to discover the conflict during a dispute later.
Setting stage payments against milestones
Typical milestones on a renovation or extension might be: deposit and mobilisation, groundworks and foundations complete, structure watertight, first fix complete, second fix complete, and final completion. Each payment should correspond to something a client can see or a professional can verify has actually happened.
Payment schedules tied to dates rather than milestones create risk for whichever side the programme runs against — the client pays for work not yet done if the job runs behind, or the builder funds materials and labour without matching cash in if it runs ahead.
How variations get priced within the contract
Almost every project changes in some way once it starts, and the contract should set out a clear mechanism for this: a variation is raised in writing, priced before the work proceeds, and agreed by both parties before it is carried out. This avoids the variation only surfacing as a surprise on the final invoice.
A contract with no variation mechanism at all tends to produce disputes precisely because there's no agreed process for what happens when the inevitable change turns up.
Retention and the final account
Some contracts include a retention — a small percentage of the total held back until any snagging is resolved, released after a defects period rather than at practical completion. This gives the client leverage to get outstanding items fixed without withholding the entire final payment.
Where retention isn't used, an agreed final completion payment released only once a written snagging list is closed serves a similar purpose, provided both sides agree what 'closed' actually means.
Why the contract matters even between people who trust each other
Many domestic jobs are agreed between people who get on well and see little need for formal paperwork, but the contract's real value shows up if something unexpected happens — an illness, a supply chain delay, a disagreement over a variation. Having the terms written down removes the need to reconstruct a verbal agreement from memory under pressure.
A short, plain-English contract covering scope, price, payment stages, variations and a defects period is enough for the great majority of domestic projects — it doesn't need to run to dozens of pages to do its job.
Common questions
How much deposit is reasonable before work starts?+
This varies by project size and materials involved, but a deposit should reflect genuine mobilisation costs — ordering long-lead materials, booking trades — rather than being a large upfront sum with little built to show for it.
What happens if I refuse to sign off a variation?+
A properly run contract means unsigned variations simply don't proceed, and the original scope continues as agreed. This is exactly why raising and pricing variations in writing before work starts matters.
Is retention still common on domestic jobs?+
It's less universal on smaller domestic projects than on commercial contracts, but it remains a useful and reasonable mechanism, particularly on larger renovations, to keep leverage over snagging until it's genuinely finished.
Ask to see a sample contract before you commit
We're happy to talk through our contract terms and payment stages before any work is agreed.