Extra costs
Builder asking for more money? What homeowners should check first
A request for more money is one of the most unsettling moments in a home project. It is also one of the most common, and it is not automatically a warning sign. What matters is understanding what the extra cost is for, whether it sits inside or outside the agreed scope, and what you are entitled to see before you agree to anything.
First, work out which kind of extra cost this is
Extra costs usually fall into a small number of categories. Naming the category is the quickest way to turn an anxious conversation into a practical one.
- A variation: a change to the agreed works, whether you asked for it or the builder proposes it.
- A provisional sum being firmed up: an allowance in the original quote that was always going to be priced properly later.
- A prime cost item: an allowance for a product you had not chosen yet, such as tiles, sanitaryware or a kitchen.
- Discovery on site: something genuinely unforeseen behind a wall, under a floor or in the ground.
- A pricing error or an omission from the original quote: work that should have been included but was not.
Ask for a breakdown, in writing, before you respond
A reasonable builder will expect this and most will already have the numbers. A breakdown is not a challenge to their honesty; it is how professional projects are run.
- What exactly is being added, described in ordinary language.
- Why it is needed and when it was discovered.
- Labour, materials and any subcontractor cost, shown separately where possible.
- Any credit or omission: work no longer required should reduce the total.
- The effect on the programme and on the payment schedule.
Compare it against the original quote, not against your memory
Read the original quote and specification again before you reply. The question is not 'does this feel expensive' but 'was this inside or outside what I agreed to pay for'. Exclusions, allowances and the scope of works section usually answer it.
If the original quote was vague on the point in dispute, that is useful information too. It tells you the ambiguity was there from the start, and that a fair outcome is likely to sit somewhere between the two positions.
Do not approve blindly, and do not stall indefinitely
Both extremes cause problems. Approving on the spot to avoid an awkward conversation is how projects drift far past budget. Refusing to engage for weeks stops the job and often costs more in standing time.
A short, written response the same week is almost always the right pace: acknowledge the request, ask for the breakdown, and agree a date to decide.
Case-style example
A typical example
A homeowner mid-way through a rear extension is told the foundations need to go deeper than allowed for, at an extra cost of several thousand pounds. The request arrives verbally, on site, on a Friday.
Rather than agreeing or refusing, the homeowner asks for the depth actually required, the building control inspector's instruction, the extra concrete and labour priced separately, and the effect on the completion date. The builder provides it on Monday. The figure is broadly fair, one line is duplicated, and the corrected total is agreed in writing the same day.
Nothing adversarial happened. The homeowner simply asked the questions that made the number checkable.
How The Construction Clinic helps with this decision
The Construction Clinic helps you work out which kind of extra cost you are looking at, what a reasonable breakdown should contain, and what to say in reply. We do not negotiate with your builder or price the work; we help you understand the decision well enough to make it calmly and in writing.
Common questions
Questions homeowners ask about this
Is it normal for a builder to ask for more money mid-project?
Yes, it is common. Conditions on site are rarely fully known when a quote is prepared, and homeowners often change their minds about finishes. What should not be normal is an extra cost arriving without explanation, without a breakdown, or after the work has already been done.
Do I have to pay for extra work I did not agree to?
Generally you are liable for work you instructed or agreed to, including verbally. Work carried out without your agreement is a much weaker claim. This is exactly why agreeing variations in writing before they happen protects both sides.
What is a provisional sum and why has it gone up?
A provisional sum is an allowance for work that could not be priced accurately at quote stage. When the real scope becomes clear it is re-priced, and the difference is added or credited. A provisional sum going up is not an extra; it is the allowance being replaced by an actual cost.
What should a written variation include?
A description of the change, the reason for it, the cost (with any credit for omitted work), the effect on the programme, and a date. Both parties should have a copy before the work proceeds.
Can I refuse an extra cost?
You can decline a variation you did not request, and you can ask for alternatives. Where the extra is genuinely necessary for the work to be safe or compliant, refusing it usually means changing the scope rather than avoiding the cost.
Should I stop payments while we discuss an extra?
Withholding an entire agreed stage payment over one disputed item usually escalates matters. It is generally better to pay what is properly due for completed work and keep the disputed sum separate and clearly identified in writing.
When should I get independent professional advice?
When the sums are large relative to the contract, when the same dispute keeps recurring, or when you are being asked to make a structural or compliance decision you do not understand. A single paid hour with a surveyor early is far cheaper than a dispute later.