Extra work after a quote is accepted: how to agree changes

A fixed quote does not become flexible just because the job has started. If the customer asks for something different, or concealed work reveals a genuine problem, describe the change, price it and get clear approval before you carry it out. That short pause protects both sides.

Use one rule throughout the job: record what has changed, why it is outside the accepted quote, what it will add or remove from the price, how it affects timing and who approved it. Do not rely on a quick conversation at the front door.

Why the accepted quote still matters

Once a customer accepts a quote, the written scope and price form the starting point for the job. Citizens Advice describes a quote as a promise to do the stated work for the agreed price. A trader cannot normally add to that price unless the customer asks for extra work, agrees to necessary extra work, or the original quote contained an obvious genuine mistake. Read the Citizens Advice guidance on quoted prices.

This does not mean you have to absorb work that was never included. It means the change needs its own agreement.

What counts as a change to the work?

A variation can increase, reduce or alter the original scope. Common examples include:

• the customer choosing a different product or specification;

• asking for another room, fitting or circuit to be added;

• removing part of the work;

• changing the layout after first fix has begun;

• concealed damage or unsuitable existing work becoming visible;

• a change to access, timing or sequencing that creates extra cost;

• work required by a third party that was not part of the accepted scope.

Not every difficulty is a chargeable extra. Correcting your own mistake or completing something already promised in the quote is not a customer variation. The first question is always whether the work is genuinely outside the agreed scope.

A five-step process for agreeing extra work

1. Stop and point back to the quote

Show the customer where the accepted quote ends. Keep the conversation factual. "That wall was priced for patching, not full replastering" is clearer than "That will cost extra".

2. Describe the change

Write one clear sentence about the new work. Add a photo where the reason may be hard to explain later, such as corroded pipework found below a floor or a damaged cable hidden behind a fitting.

3. Price the effect

State the extra cost or credit. Include labour, materials, plant, waste and VAT where relevant. If you cannot fix the total until more is opened up, explain how the price will be calculated and set a limit before asking for another decision.

4. Explain the effect on the programme

Say whether the change moves the completion date or affects another trade. A customer who approves the extra price may still be surprised if it adds three days to the job.

5. Get express approval

Ask the customer to accept the change in writing before work starts. An email, signed variation or clear online acceptance is stronger than a remembered conversation. Keep the approval with the original quote and job record.

Section 50 of the Consumer Rights Act says that information a trader gives about a service can become part of the consumer contract, and a later change must be expressly agreed. See section 50 of the Consumer Rights Act 2015.

What if you uncover a problem halfway through?

Take a photograph, make the area safe and explain what you found. Give the customer sensible options where possible. For example:

• repair the newly discovered problem now for an agreed amount;

• stop at a safe point while they consider it;

• return the area to the condition covered by the original quote, where that is possible and reasonable.

If the work is urgent for safety or to prevent damage, record why immediate action was necessary and get approval as clearly as the circumstances allow. Do not use urgency to avoid discussing the cost.

Sample variation wording

This fictional example shows the information to record. It is not a legal template for every contract.

Variation V-02 to quote QT-105

Change: replace the section of corroded hot-water pipe found below the bathroom floor after the old bath was removed.

Reason: the pipe was concealed and could not be inspected when quote QT-105 was prepared. A photograph is attached.

Price change: add £240 plus VAT for materials, labour and testing.

Time change: add half a working day. The expected completion moves from Thursday to Friday.

Approval: I approve this variation and the revised contract total of £[amount].

How to invoice a variation cleanly

Do not bury the extra inside a final total the customer has never seen. On the invoice, refer to the original quote and list each approved variation separately. Show any credit for removed work as clearly as an added charge.

For a long job, decide whether the change is due with the next stage payment or at completion. Record the choice in the variation so the customer knows when it will be billed.

Four habits that prevent arguments

• Write a better original scope. Use the trade quote checklist to record assumptions and exclusions before the job starts.

• Do not price from memory. Calculate the labour, materials and effect on other work.

• Do not carry on while approval is vague. "Should be fine" is not the same as accepting a new price.

• Keep one record. Store the accepted quote, photographs, variation and invoice together.

Government guidance says consumer contract terms should be transparent and warns against clauses that give a trader a blank cheque to change the work or price without the customer's consent. See the CMA guidance on changing consumer contracts.

TradePilot keeps the customer, quote, job, photos and invoice connected. It can help preserve the job record, but it does not decide whether a variation is legally valid or agree the extra work for you. See how the job record stays connected in TradePilot.

Written by Chris, founder of TradePilot. This guide is general information, not legal advice. Contracts and consumer rights depend on the exact agreement and circumstances. Get legal or Trading Standards advice where a dispute or significant change is involved.