If your builder is charging for a variation you never agreed to, the first question is whether the variation was agreed in the form your state’s home building law requires. In New South Wales and Victoria that means a document you signed. In Queensland it means your agreement in writing before the varied work started, and a variation document with the price in it. If those are missing, pay the part of the invoice that is genuinely due, and dispute the rest in writing, citing the rule.
Claim Done drafts that letter. The Variation Dispute costs A$49 and sets out the claim you are disputing, the rule for your state, what you will pay now and what you do not accept. You approve it before it is emailed to the builder. The same letter handles the other common overcharge: a progress claim for a stage that is not finished.
Does a variation have to be in writing and signed?
In most of the country, yes. The details differ.
New South Wales. Section 7E of the Home Building Act 1989 says a contract must include, and is taken to include, each term in Part 1 of Schedule 2. Clause 1(2) of that schedule reads: any agreement to vary the contract, or the plans and specifications, “must be in writing signed by or on behalf of each party”. A site conversation with the supervisor is not a signed agreement.
Victoria. The Domestic Building Contracts Act 1995 covers major domestic building contracts, which Consumer Affairs Victoria says means work worth more than $10,000. A builder who wants a variation must give you a notice of what it is, why, any delay and its cost (s 37(1)), and must not carry it out without your signed consent attached to that notice (s 37(2)), unless a building surveyor’s notice or order required it. A variation you ask for needs your signed request attached to the builder’s notice (s 38(5)), unless it needs no permit change, causes no delay and adds no more than 2% to the original price (s 38(2)).
Queensland. Schedule 1B of the Queensland Building and Construction Commission Act 1991 is stricter on timing and looser on form. The builder must not start the varied work before you agree to the variation in writing (s 40(5)), and must give you a copy of the variation in writing within 5 business days of agreeing it or before the work starts, whichever is first (s 40(2)). The document must describe the variation and state the price change and when it is payable (s 41(2)), and an increase cannot be required before the varied work starts (s 41(3)).
Western Australia. Building and Energy’s Home Building Contracts Act fact sheet says that usually any variation has to be in writing, show the date and be signed by both parties, with a copy given to the home owner before the variation work starts.
South Australia, Tasmania, the Australian Capital Territory and the Northern Territory. We found no statutory variation rule we could verify, so rely on your contract’s variation clause.
What if you agreed by text message or email?
This is where Queensland parts company with New South Wales and Victoria.
In New South Wales and Victoria the rule asks for a signature. A text saying “yep go ahead” is not that.
Queensland’s s 40(5) asks for agreement “in writing” and says nothing about a signature. The Acts Interpretation Act 1954 defines writing to include “any mode of representing or reproducing words in a visible form”, so a text or an email agreeing to the variation may well count. That does not end the argument. The builder still owes you a variation document stating the price change (s 41(2)) and the copy s 40(2) requires. A text that says “go ahead” with no price in it leaves the price open to dispute.
The practical consequence: in Queensland, argue about the price and the paperwork, not about whether you agreed. In New South Wales and Victoria, the missing signature is the point.
Ready to put it in writing?
Answer 3 quick questions to check you have the details your document needs, and see your next step.
1. Who did the work?
2. How much is at stake?
3. Do you have it in writing?
Your result is ready. Where should we send it?
Can the builder still be paid for an unwritten variation?
Sometimes, so do not tell the builder they will never be paid.
In Victoria, s 37(3) says a builder is not entitled to recover money for its own variation unless it complied with s 37 and the variation was made necessary by circumstances it could not reasonably have foreseen, or VCAT finds exceptional circumstances or significant or exceptional hardship and that recovery would not be unfair to you. A narrow door, but a door.
Queensland’s Schedule 1B s 44 says a builder’s failure to comply with the Act does not by itself make the contract illegal, void or unenforceable. So do not call the claim void. Say the variation was not agreed or documented as ss 40 and 41 require.
In New South Wales, say the variation was not agreed in the signed written form Schedule 2 requires and that you do not accept it as agreed. That is accurate, and enough to put the charge in dispute.
Ready to put it in writing?
Claim Done drafts your letter, application, response or agreement from your answers, from A$29. You review and approve it before anything is sent or lodged. No lawyer's retainer, no subscription.
Can the builder bill for a stage that isn’t finished?
Not in the states that regulate progress payments.
In New South Wales, s 8A applies to contracts above the prescribed amount. A progress payment is authorised only if it is a specified amount or percentage payable after completion of a specified stage described in clear and plain language (s 8A(2)(a)), or a payment for work already performed or costs already incurred, supported by invoices, receipts or other documents (s 8A(2)(b)). Section 8A(4)(a) prohibits demanding or receiving a progress payment that is not authorised. The NSW Government also warns that an additional or early payment that is not an authorised progress payment may affect your ability to recover it under home building compensation cover if the builder later fails.
Victoria’s s 40(2) caps what a builder can demand, recover or retain at each stage of a major domestic building contract. For a contract to build all stages the caps are 10% at base stage, 15% at frame, 35% at lock-up and 25% at fixing. Lock-up is defined in s 40(1): external wall cladding and roof covering fixed, flooring laid, and external doors and windows fixed (even if temporary). Two window openings with nothing fixed in them, not even temporary windows, means the house is not at lock-up. Section 42 bars a demand for final payment until the work is complete and you have the occupancy permit or certificate of final inspection.
In Queensland, Schedule 1B s 34(1) says a builder must not claim an amount, other than a deposit, unless it is directly related to the progress of the work at the site and is proportionate to (or less than) the value of the work it relates to. Western Australia’s fact sheet gives the plainest example in the country: a builder cannot demand a progress payment for bricks until the bricks have been delivered to the site. In South Australia, s 30(1)(a) of the Building Work Contractors Act 1995 allows a demand only for a genuine progress payment for work already performed, and under s 30(3) you are not obliged to pay a progress payment unless the builder has asked for it by written notice (subject to the Security of Payment Act exception in that section).
| State | Variation rule | Progress claim rule | Deposit cap |
|---|---|---|---|
| New South Wales | In writing, signed by or for each party (Home Building Act 1989, Sch 2 cl 1(2)) | Only authorised progress payments: a completed, described stage or work already done (s 8A) | 10% (s 8) |
| Victoria | Builder’s notice plus your signed consent or signed request (Domestic Building Contracts Act 1995, ss 37, 38) | Stage caps in s 40; no final payment until complete with occupancy permit or final inspection (s 42) | 10% under $20,000; 5% at $20,000 or more (s 11) |
| Queensland | Agreed in writing before the work starts; document with price and timing (QBCC Act Sch 1B ss 40, 41) | Directly related to progress and proportionate to the work (Sch 1B s 34) | 10% level 1, 5% level 2 (Sch 1B s 33) |
| Western Australia | Usually in writing, dated, signed by both, copy before the work starts (Building and Energy) | Only for work performed or materials supplied | 6.5% |
| South Australia | Your contract’s variation clause | Genuine progress payment for work already performed; written request needed (s 30) | Not covered here |
| Tasmania, Australian Capital Territory, Northern Territory | Your contract’s variation clause | Your contract’s payment schedule | Not covered here |
What should you pay now, and what should you dispute?
Split the invoice into three piles:
- Work that is done. A genuinely complete stage, or a variation you signed. Pay it on time; holding back money clearly owed hands the builder an argument.
- Charges you dispute outright. A variation with no signed document (New South Wales, Victoria, Western Australia), one started before you agreed in writing (Queensland), or a claim for an unfinished stage.
- Charges you accept in principle but not at that price. Extra work you asked for, where no price was put in writing.
Then put your position in writing within days. State the claim number, date and amount, what you will pay now and when, what you dispute and why, and the documents you want: the signed variation and how the price was calculated, or evidence the stage is complete. The amount you pay plus the amount you dispute should equal the claim. If a $163,800 lock-up claim arrives while two windows are still missing, the letter says you will pay it when lock-up is reached as s 40(1) defines it, and asks the builder to tell you when it is ready for inspection.
What happens if the builder won’t back down?
The next step is your state’s building regulator, and in three states you cannot skip it. In New South Wales, NCAT says home building disputes must first be referred to the regulator (now Building Commission NSW) before it will accept an application, unless an exemption applies. In Victoria, s 56 of the Domestic Building Contracts Act 1995 bars a VCAT application about a domestic building work dispute without a certificate of conciliation from the Building and Plumbing Commission’s service. In Queensland, s 77(2) of the QBCC Act bars a QCAT application until you have complied with the QBCC’s process. In Western Australia, a variation dispute is a home building work contract complaint to the Building Commissioner, generally within three years.
If the variation is one item in a wider fight (unfinished work, defects, delay), the Building Dispute Pack (A$97) prepares a notice of dispute, a complaint statement for your regulator and a chronology and evidence schedule. If the builder has stopped work and kept your money, see contractor walked off the job: how to get your deposit back.
What does Claim Done’s Variation Dispute letter do?
Claim Done is not a law firm. The Variation Dispute is a flat A$49 letter drafted from your answers in about five minutes: what you dispute, the claim details, whether you agreed in writing, by text or not at all, and the figures.
The letter applies your state’s variation and progress payment rules to your facts, states what you will pay now and what you dispute, asks for the supporting documents, gives the builder 14 days to withdraw, amend or substantiate the claim, and names your regulator’s process as the next step. It never calls the contract void and never refuses to pay what is due. You approve it, and then it is emailed to the builder. No retainer, no subscription.
Facts checked against the Home Building Act 1989 (New South Wales, version current from 10 June 2026), the Domestic Building Contracts Act 1995 (Victoria, version 094), the Queensland Building and Construction Commission Act 1991 (Schedule 1B), the Acts Interpretation Act 1954 (Queensland), the Building Work Contractors Act 1995 (South Australia, version of 15 January 2026), and the Building and Energy, Consumer Affairs Victoria, NSW Government and NCAT pages linked above on 29 September 2026.
Your next step: find the claim or invoice and your contract’s payment stages, then start your Variation Dispute letter before the payment falls due. Every service is on the pricing page.
Frequently asked questions
Can a builder charge for a variation I never signed?
In New South Wales and Victoria the variation has to be agreed in a document you sign, so an unsigned variation can be disputed as not agreed. That does not mean the builder can never be paid: in Victoria, VCAT can allow recovery in exceptional circumstances or hardship where it would not be unfair to the owner. State your position in writing and ask for the signed variation document.
Does a text message count as agreeing to a variation in Queensland?
It may. Schedule 1B s 40(5) of the QBCC Act requires agreement in writing but not a signature, and Queensland's Acts Interpretation Act 1954 defines writing to include any mode of representing words in visible form. The builder must still give you a variation document stating the price change and when it is payable, and cannot ask for the increase before the varied work starts.
Should I stop paying the builder while the variation is in dispute?
Pay the parts of the claim that are genuinely due, such as a completed stage, and dispute only the variation or the unfinished stage, in writing, with the figures. Refusing to pay undisputed amounts gives the builder a complaint of its own.
My builder claimed lock-up but the windows are not in. Do I have to pay?
In Victoria, lock-up stage under s 40(1) of the Domestic Building Contracts Act 1995 needs external wall cladding and roof covering fixed, flooring laid and external doors and windows fixed, even if temporary. If those are not done, the stage is not complete, and you can say you will pay the claim when it is and ask to be told when it is ready for inspection.
Does Claim Done send the letter for me?
You review and approve the letter first. Claim Done then emails it to the builder, or you can download it and send it yourself. Claim Done does not lodge regulator complaints; you do that on the regulator's own form.
What happens when you put the builder on formal notice
Same problem. What a prepared case looks like.