Your Builder Is Asking for More Money: What to Do, Step by Step

First, check whether you have a quote or an estimate

Find the document your builder gave you before work started. The word at the top matters more than most people think.

Citizens Advice explains the difference for England. A quote is a fixed price. An estimate is the trader's best guess. A trader can't charge more than they quoted unless there is a good reason. And they can't charge you more because their own costs went up after the quote.

If you have a building contract, read its sections on changes, provisional sums and payment. Those sections decide most arguments about money.

Why builders ask for more money mid-job

Here is the part most builders won't say out loud. Many price rises are built in before the job starts.

Homeowners often choose the lowest quote. Builders know it. So the quote that wins is often the one that left the most out. Margins in building are thin, and a missed item can wipe out the profit on a job. When that happens, the builder needs the money back from somewhere.

That doesn't make every request a trick. Cash flow is a real problem for small firms. A builder short of money mid-job may be asking because the alternative is walking off.

We price risk too. On our own quotes you will see it as allowances and exclusions, written down before you sign. With us, a change is only agreed in writing and priced before the work starts.

The FMB found that 35% of people who hired a builder were hit with unexpected extra costs. Checkatrade found 41% said the final cost was higher than the quote.

Fair reasons a price goes up

These are the reasons where, in our view, a builder is entitled to ask. Even then, the extra should be agreed in writing before the work, not after.

1. You changed the work. A different tile, a moved wall, an extra socket. Every change you ask for can carry a cost and extra time.
2. A hidden problem appears. Rotten joists behind a ceiling, or an old wall with no foundation. A good contract says how these are priced.
3. A provisional sum is replaced with the real cost. A provisional sum is an allowance for work nobody could price yet. When the real cost is known, the figure moves up or down.
4. You agreed a price-adjustment clause. Some contracts let prices move with material costs. If you signed one, it applies.
5. You caused a delay. Late decisions or late items you supply yourself can cost the builder time on site.

Reasons that are not your problem

These are the requests to push back on. Each one is the builder's risk under a fixed quote.

1. Their costs went up after the quote. Citizens Advice says a trader can't charge more for this.
2. They missed something on the drawings. If it was shown and they didn't price it, that is their pricing mistake.
3. They under-priced to win. A quote that was too low is not a reason to pay more later.
4. They can't find labour. Trade shortages are real, but they are part of running a building firm.
5. Extras you never asked for. Ask which instruction of yours the work came from, and when.

Your rights as a homeowner

The Consumer Rights Act 2015 sets three basic rules for a service. The builder must carry out the work with reasonable care and skill. Where the price is not fixed, you pay a reasonable price, and no more. Where the time is not fixed, the work should be done within a reasonable time.

What counts as reasonable is a question of fact. In practice, that means evidence: other prices, photos, messages and the drawings.

Homeowners are mostly outside the Construction Act, which is written for commercial contracts. So on your own home, things like the right to stop work over unpaid money depend mainly on your contract. Small claims up to £10,000 can go to the county court's small claims track.

What to do when your builder asks for more money

Work through these steps in order. In our experience, many disputes settle once both sides see the same breakdown.

1. Don't agree or refuse on the spot. Say you will reply in writing within two working days.
2. Ask for the request in writing. It should say what changed, the labour, materials and time, and why it is extra.
3. Check it against your paperwork. Compare it with the quote, the drawings, the specification and your messages.
4. Sort each item into fair, unfair or unclear. Use the two lists above.
5. Get an independent view on price. Another builder or a quantity surveyor can tell you if the figure is reasonable.
6. Reply in writing with an offer. Agree the fair items, reject the unfair ones and propose a figure for the rest.
7. Escalate only if talking fails. Use a trade association scheme, the Citizens Advice consumer service, or a solicitor.

Keep paying what you agree is due. Holding back everything can give the builder a reason to stop. Holding back nothing gives you no leverage. Your solicitor can tell you where the line sits in your contract.

Commercial clients: the notices decide it

On a commercial job, the Construction Act changes the rules. Payment notices must go out within 5 days of the payment due date.

If you plan to pay less than the notified sum, you must serve a pay less notice before the final date for payment. Where the contract is silent, the statutory Scheme sets this at 7 days before the final date.

Miss the notice, and you may have to pay the full sum and argue later. A contractor who isn't paid can also suspend work after giving notice.

Read our guide to the construction adjudication process in the UK for the next step. The payment section of our JCT Design and Build Contract guide covers how payments work under the standard form.

How to stop it happening on your next project

The best time to deal with a price rise is before you sign. Our guide on how contractors win on price and make it back explains where the gaps hide.

Changes after signing are called variations. Our guide to variations in construction contracts shows how to price and record them. For bigger projects, a clear brief prevents most arguments. See how to brief a contractor.

Most price rises can be settled with paperwork and a calm conversation. Planning the next stage of your project? Want a builder who agrees the price before the work? Book a site visit.