Contractor Wants More Money After Job: How to Respond Legally

You agreed on a price. The contractor finished the work. Now they’re demanding more money.

This situation puts you in an uncomfortable position. Pay the extra demand and you might be overpaying for work already covered by your original agreement. Refuse to pay and you risk threats, liens, or tribunal claims. This guide shows you how to respond properly and protect your legal position.

Why contractors demand extra money after completion

Contractors typically demand additional payment after finishing a job for these reasons:

Scope creep without documentation — the project expanded beyond the original quote, but no written variation was agreed

Underquoting — the contractor miscalculated costs or labour hours and now wants to recover the shortfall

Discovered issues — unexpected structural problems, asbestos, or other complications emerged during the work

Client-requested changes — you asked for modifications or upgrades mid-project, and the contractor claims these weren’t included in the original price

Disputed quality — you withheld final payment due to defects or incomplete work, and the contractor is now claiming extra costs to remedy issues

Dishonest practice — some contractors deliberately lowball quotes to win jobs, then inflate invoices once the client is committed

The legal question is simple: does the contractor have a contractual entitlement to the extra money, or are they trying to renegotiate a completed deal?

What your original contract says matters

Before you respond to any demand for extra payment, retrieve your original contract or quote.

Written contracts — check for clauses covering variations, additional work, unforeseen circumstances, and payment terms. Most properly drafted contracts require written approval before any variation increases the price.

Quotes and estimates — a fixed-price quote is generally binding. An estimate is not. If your contractor provided a quote and the scope hasn’t changed, they cannot unilaterally increase the price after completion.

Verbal agreements — harder to prove, but still enforceable. If you agreed on a price verbally and the contractor completed the work to that scope, the original price stands unless you agreed to variations.

No written agreement — the law implies a contract based on what a reasonable person would expect. If the contractor quoted $10,000 and you accepted, that’s the contract, even without paperwork.

Under Australian Consumer Law, any term that allows a contractor to unilaterally increase the price after completion may be considered unfair and unenforceable.

How to respond without admitting liability

When a contractor demands extra money after finishing the job, your response needs to be measured, documented, and legally sound. Do not ignore the demand.

Step 1: Request a detailed breakdown

Reply in writing (email is fine) and ask the contractor to provide:

• Itemised list of the additional work or costs claimed
• Dates when the additional work was performed
• Reference to any written variation or approval you provided
• Copies of invoices, receipts, or supplier quotes supporting the claim

This puts the burden on the contractor to justify the demand. Many inflated or opportunistic claims collapse at this stage when the contractor cannot provide proper documentation.

Step 2: Compare the claim against your contract

Review the itemised breakdown against your original agreement. Ask yourself:

• Was this work included in the original scope?
• Did I approve any variation in writing?
• Were there genuinely unforeseen circumstances that required extra work?
• Is the contractor claiming for defects they caused themselves?

If the additional work was genuinely outside the original scope and you approved it (even verbally), you may owe something — but only for the reasonable value of that extra work, not whatever the contractor now decides to charge.

Step 3: Respond in writing with your position

Draft a clear, factual response. Do not get emotional. Do not threaten. State your position based on the contract and the facts.

Example response structure:

> “Thank you for your invoice dated [date] claiming an additional $[amount]. > > I have reviewed this claim against our original agreement dated [date] for $[original amount]. The original scope included [list key items]. > > The additional work you have itemised was [included in the original scope / not approved by me in writing / required due to defects in your original work]. > > Based on the original agreement, I do not accept that any additional payment is owing. The agreed contract price of $[amount] has been paid in full. > > If you believe you have a legal entitlement to additional payment, please provide copies of any signed variation or written approval I provided.”

This response does not admit liability, does not agree to pay, and puts the onus back on the contractor to prove their claim.

Step 4: Do not make partial payments “without prejudice”

Some contractors will pressure you to pay part of the disputed amount “as a gesture of goodwill” while the dispute is resolved. Do not do this. Any payment you make can be interpreted as acceptance of the contractor’s claim, weakening your position if the matter goes to tribunal.

If you genuinely believe some additional payment is fair, document it clearly as a settlement offer, not an admission.

What the contractor can (and cannot) legally do

Contractors have limited legal options to recover disputed amounts after completing a job.

What they can do:

• Send further invoices and demand letters
• Lodge a payment claim under security of payment legislation (if applicable to their trade)
• File a claim in the relevant state tribunal (NCAT, VCAT, QCAT, etc.)
• Lodge a caveat on your property title (only if they can prove an interest in the land, which is rare)

What they cannot do:

• Remove completed work or materials without a court order
• Harass, threaten, or intimidate you
• Publish defamatory statements about you online or in reviews
• Claim amounts for defects they caused or work not performed

If a contractor threatens illegal action, document it. Threats and harassment can strengthen your position if the dispute escalates.

When you might owe something (and when you don’t)

You may have a legal obligation to pay additional amounts if:

• You requested extra work or changes mid-project and the contractor performed that work
• Genuinely unforeseen circumstances arose (e.g., structural issues discovered during renovation) and the contractor notified you before proceeding
• The original contract included a clause allowing price adjustments for specific reasons, and those reasons occurred

You do not owe additional amounts if:

• The contractor simply underquoted and wants to recover their mistake
• The additional costs relate to defects or delays caused by the contractor
• No written variation was agreed and the work was within the original scope
• The contractor is inflating the claim opportunistically after you’ve already paid

Australian contract law does not allow one party to unilaterally change the price after performance. If the contractor agreed to do the job for $10,000, they cannot later decide it should have been $15,000 just because they miscalculated.

What happens if the contractor takes it further

If your response does not resolve the dispute, the contractor’s next step is usually a tribunal claim. Each state has a civil and administrative tribunal that handles building and trade disputes:

• NSW: NSW Civil and Administrative Tribunal (NCAT)
• VIC: Victorian Civil and Administrative Tribunal (VCAT)
• QLD: Queensland Civil and Administrative Tribunal (QCAT)
• SA: South Australian Civil and Administrative Tribunal (SACAT)
• WA: State Administrative Tribunal (SAT)
• TAS: Tasmanian Civil and Administrative Tribunal (TasCAT)
• ACT: ACT Civil and Administrative Tribunal (ACAT)
• NT: Northern Territory Civil and Administrative Tribunal (NTCAT)

Tribunal claims are designed to be accessible without lawyers. If the contractor files a claim, you will receive a notice to respond. At that point, you can prepare a defence using ClaimDone’s tribunal defence documents, or engage a lawyer if the amount or complexity justifies it.

Most building disputes under $25,000 are resolved at tribunal without legal representation. The tribunal will review the original contract, any variations, correspondence, and evidence from both parties before making a decision.

Final checklist: Responding to a contractor’s extra demand

• Retrieve your original contract, quote, or agreement
• Request a detailed, itemised breakdown of the additional claim
• Compare the claim against the original scope and any approved variations
• Respond in writing, stating your position clearly and factually
• Do not admit liability or make partial payments without proper documentation
• Keep copies of all correspondence, invoices, and evidence
• If the contractor threatens illegal action, document it
• If the dispute escalates, consider tribunal proceedings or legal advice

The contractor’s demand does not automatically create an obligation. You are entitled to hold them to the original agreement unless there is a clear contractual basis for the additional charge.

How Claim Done helps you respond properly

ClaimDone’s Legal Response service generates a professionally formatted reply to the contractor’s demand. You upload the original contract, the contractor’s demand, and any relevant correspondence. Our Proprietary AI Engine drafts a response that protects your position without admitting liability.

The response is prepared in 60 minutes, costs $97, and is tailored to your specific dispute and state. This is not legal advice — it’s a legal-style document you can send yourself or provide to a lawyer if the dispute escalates. For complex disputes involving significant amounts, defective work, or potential tribunal proceedings, consult a qualified Australian lawyer.

Upload your documents now and get your response prepared today. No subscription. Flat $97 fee. See how Claim Done works.

Frequently Asked Questions

Can a contractor legally demand more money after finishing the job?

Only if there is a contractual basis for the additional charge — such as approved variations, genuinely unforeseen work, or a contract clause allowing price adjustments. A contractor cannot unilaterally increase the price after completion simply because they underquoted or miscalculated costs.

What if I agreed to extra work verbally during the project?

Verbal agreements can be binding, but they are harder to prove. If you genuinely approved additional work and the contractor performed it, you may owe a reasonable amount for that work. However, the contractor must prove the agreement existed and that the work was outside the original scope.

Do I have to pay if the contractor threatens to take me to tribunal?

No. A threat to file a tribunal claim does not create an obligation to pay. If the contractor believes they have a valid claim, they can file it and the tribunal will decide based on the evidence. You are entitled to defend the claim if you believe the additional charge is not justified.

What if the contractor refuses to fix defects unless I pay the extra amount?

This is not lawful. The contractor has an obligation to complete the work to the agreed standard under the original contract. Refusing to remedy defects unless you pay a disputed additional amount may be a breach of contract and a breach of consumer guarantees under Australian Consumer Law.

Can a contractor put a lien or caveat on my property for unpaid amounts?

In most cases, no. Caveats can only be lodged if the contractor has a legal interest in the property, which is rare in standard residential building contracts. Some states allow security of payment claims for certain trades, but these have strict procedural requirements and time limits.