It’s easy to treat a building contract as paperwork to sign so the real work can start. In reality, it’s the single document that governs your entire relationship with your builder — what gets built, what you pay and when, how long it should take, and what happens the moment anything changes. Understanding it properly before you sign is one of the best protections you have.
What the scope of works actually needs to say
The contract should define exactly what’s being built by referencing your architectural drawings, structural engineering, material and finish specifications, and any external works like driveways, fencing, or landscaping. Vague or generic scope wording is where disputes are born — if the contract doesn’t clearly say what’s included, you and your builder may have two very different ideas of what “complete” looks like.
How payments are typically staged
Most Australian residential building contracts use milestone-based payments tied to physical progress on site — commonly a deposit, then payments at base/footings, frame, lock-up, fixing, and practical completion. This structure ties what you pay to what’s actually been built, rather than to an arbitrary calendar, and it’s one of the key consumer protections built into standard residential contracts.
Timelines — realistic, not rigid
A well-written contract sets out an expected construction duration while acknowledging, explicitly, that weather, approvals, and site conditions can shift it. What actually matters isn’t whether the timeline holds perfectly — it rarely does on any project — but whether the contract has a clear, fair process for how delays are assessed, communicated, and (where relevant) compensated.
The contract terms worth genuinely understanding
Prime cost (PC) items are dollar allowances built into the contract for selections that haven’t been finalised at signing — things like tapware, appliances, or flooring. If what you eventually choose costs more than the allowance, you cover the difference; if it costs less, you’re typically credited the balance. It pays to ask what the allowances are based on, so you’re not surprised later.
Provisional sums cover work that genuinely can’t be fully priced upfront — excavation depth, for example, or landscaping scope — because the final cost depends on conditions only discovered once work is underway.
Variations are any changes to the agreed scope requested after the contract is signed, whether by you or prompted by something found on site. These should always be documented and approved in writing before work proceeds, because a variation affects both price and schedule, and verbal agreements are very hard to resolve fairly after the fact.
Practical completion is the point at which the home is substantially finished and safe and legal to occupy, even if a short list of minor defects or outstanding items remains to be finished off during the defects liability period.
What to check before you sign
Confirm that every drawing, specification, and schedule referenced in the contract is actually attached — a contract that references documents you’ve never seen isn’t one you can properly evaluate. Get absolute clarity on what’s included and what isn’t, understand exactly how variations are priced and approved, and check the defects liability and warranty terms. For a project of this size, having a solicitor review the contract before signing is a modest cost against the protection it provides — and a reputable builder won’t be offended that you asked.