Can I make changes to my build after signing the contract?
Short answer
Yes — changes during a build (called 'variations') are normal, but every variation should be agreed in writing before the work is done. The contract should include a variation process: usually a written instruction from the homeowner, a quoted impact on cost and timeline from the builder, and a signed acceptance before the work starts. Unwritten variations are the single biggest source of build disputes.
Source: NZS 3902 / NZS 3911 standard residential contracts. Updated May 2026.
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Check a builderKey facts
- Variations are normal — most builds have 5-15 of them
- Always agree in writing BEFORE the work is done
- Cost AND timeline impact should be specified
- Verbal 'just do X' on site costs more than you think
- Unwritten variations are the #1 source of disputes
The right variation process
Homeowner requests the change in writing (email is fine). Builder responds with: scope of the change, cost impact, timeline impact. Homeowner signs/accepts before work starts. Builder issues an updated invoice schedule including the variation.
Most builders have a one-page Variation Form template. If yours doesn't, ask them to use one. Texts back and forth on site rarely survive a dispute.
Common variation traps
Verbal agreement on site — the builder remembers a $400 add, you remember $200, the invoice comes in at $850.
'Like for like' substitutions where the substitute isn't actually like-for-like — different finish, different durability, similar price tag but cheaper to source.
Provisional sums that drift up — many contracts include 'PS' allowances for items not yet selected (tiles, fittings, paint colours). Watch these closely; they're a budget leak path.
When the builder proposes a variation
Sometimes the builder discovers a site issue and proposes a variation. That's fine. The same process applies: written scope, cost, timeline, signed by you before work starts.
If the variation is to fix a defect they should have caught originally, push back. You shouldn't be paying twice for the same scope.
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Related questions
Sources: NZS 3902 / NZS 3911 standard residential contracts; MBIE Building Performance — variations guidance. General information for NZ homeowners, not legal advice. Building rules change and vary by council, so confirm critical details on the official source before acting. Last updated 2026-05.