How Should I Charge for Extra Work on a Kitchen Installation?

For installers

Extra work is part of kitchen installation. Customers change their minds. Old kitchens come out and reveal things nobody could see. Plans change, products change and sometimes one small request turns into considerably more work than it first appeared. None of that is particularly unusual.

Where installers get themselves into trouble is doing the work first and trying to sort the price out afterwards. I've seen this happen plenty of times. You're already on the job, the customer asks whether you could “just” do something while you're there and it feels easier to say yes than stop everything and talk about money.

A few days later you've done several hours of work, used materials, possibly involved another trade and now have to explain why the final bill is higher than the quotation. That's a much harder conversation than the one you could have had before you started.

Bathroom installers face the same conversations. A changed layout or a problem uncovered during strip-out still needs to be explained, priced and agreed before it disappears into the rest of the job.

First, work out what kind of extra it actually is

I think it helps to separate extra work into three fairly simple categories, because they aren't all the same.

The first is something the customer has changed or added. They want another socket, an extra cupboard fitted, some additional tiling or they've changed an appliance and it now needs different work.

The second is something genuinely unforeseen. You take the old kitchen out and find rotten flooring, pipework somewhere nobody expected it, a wall in poor condition or electrical work that needs attention before the installation can continue.

The third is something you got wrong when you priced the job. That distinction matters.

If you allowed eight days and the installation takes ten because you underestimated it, that doesn't automatically make the extra two days additional work. If the original scope hasn't changed, that's normally a pricing problem rather than a variation. A variation should change the work, not simply repair a bad quote.

Customer changes should be fairly straightforward

If the customer asks you to do something that wasn't in the original scope, explain that it is additional work and tell them what it will cost before doing it. That sounds basic, but on site it's surprisingly easy not to.

The customer says, “While you're here, could you move that socket over there?” You say yes. Then another thing gets added, and another. Individually none of them seems worth stopping the job for, but by Friday you've accumulated half a day's unpaid work.

There's nothing wrong with occasionally doing a small thing as goodwill. I did plenty of that over the years. The important point is that you decide when something is goodwill. It shouldn't happen simply because you didn't feel comfortable mentioning the price.

If you decide not to charge, you can still tell the customer what you've done: “That wasn't included, but don't worry about it this time.” That makes it clear it was an extra you've chosen not to charge for rather than something that was always included.

Unforeseen work needs a different conversation

You can't see through walls and floors when you're quoting a kitchen. Sometimes the old kitchen comes out and the job underneath is different from the one you were reasonably able to price.

If you uncover something significant, stop and explain it. Show the customer what you've found where possible, explain why it matters and what needs to happen before you can continue. Then give them the cost, or explain how the cost will be worked out if you genuinely can't fix a number immediately.

What you shouldn't do is quietly spend two days sorting it and add £1,000 to the invoice at the end. The customer didn't have an opportunity to understand the problem or agree to the cost. From the installer's side, putting the extra work in writing also protects you. Three weeks later, nobody has to rely on two different memories of a conversation that happened while the kitchen was in pieces.

Don't confuse extra work with taking longer

This is the bit installers sometimes don't want to hear. A quotation is generally an agreed price for an agreed scope of work. Citizens Advice currently explains that a trader can't simply charge more than a quote without a proper reason, such as additional work being required and the customer agreeing to pay for it.

So if the job takes longer because you misjudged the fitting time, your costs rose or one of your own subbies charged you more than expected, you shouldn't automatically turn that into the customer's extra. That's part of the risk involved in giving a fixed quotation.

It is different if the work itself changes. If the customer adds work, the design changes or something genuinely outside the agreed scope is discovered, you've got a reason to discuss a variation. That distinction is why the original scope matters so much.

Price the whole effect of the change

When pricing an extra, don't only look at what the physical item costs. Suppose the customer changes something that needs another electrician visit. The additional cost isn't necessarily just the socket or cable. There might be another journey, an hour of your time reorganising things, the electrician's minimum charge, a delay to another part of the job and perhaps a return visit you hadn't allowed for.

Likewise, if a customer decides halfway through that they want a different arrangement, the change could affect several parts of the installation. Price the effect of the change, not just the object they've asked for.

This is similar to the point we've already covered around itemised quotations. A kitchen installation isn't a collection of completely independent little jobs. They all affect each other.

Sometimes the whole job needs repriced

A customer might look at the original quote and assume that removing something means the exact amount shown for that part can simply be deducted. That isn't always how it works.

If they decide their own plumber is going to take over the plumbing, for example, it could change your programme, responsibility, sequencing and number of visits. Likewise, adding something halfway through might affect work you've already done or change what another trade now needs to do.

At that point you're not necessarily adding or subtracting one isolated number. You may be repricing part of the job because the job itself has changed. Explain why. Most arguments around variations get worse when the fitter knows what has changed in their head but never properly explains it to the customer.

Put the variation in writing

This doesn't need to become a 20-page contract amendment every time somebody asks for another socket. A useful variation record can be very simple. It should make clear:

• what additional or changed work is being requested
• why it wasn't part of the original quotation
• what the extra work will cost
• whether VAT applies where relevant
• whether it affects the programme or completion date
• whether another trade or additional visit is required
• that the customer has approved it

Then keep the record with the job. A text or email confirming a small agreed change is considerably better than nothing, although for larger variations I prefer something more structured. The important thing is having a record before the work disappears into the rest of the installation.

Don't be frightened of saying the job has to pause

Sometimes the extra work is optional. Sometimes it isn't. If you uncover something that genuinely needs dealing with before you can safely or properly continue with the installation, explain that to the customer.

That doesn't mean you have a blank cheque to fix anything you like. It means there may be a point where the original installation cannot sensibly continue until the newly discovered issue has been resolved.

The customer might ask you to price it, arrange somebody else or want more information before deciding. That's fine. The mistake is continuing regardless and hoping everybody agrees about the money later.

Additional work shouldn't become a sales tactic

There's another side to this. Don't deliberately quote a job cheaply and then make your money by finding extras once you're through the door. Apart from the obvious damage that can do to your reputation, current UK guidance around consumer pricing puts a strong emphasis on prices being clear and on customers understanding unavoidable charges rather than having them added later.

Variations are there because jobs genuinely change. They shouldn't be used to repair a quotation that was never realistic in the first place. If something is normally required on the type of installation you're quoting, price it properly or make the assumption clear before the customer accepts the job.

Good variation control protects the relationship

Some installers worry that bringing up money every time a job changes makes them look difficult. I think the opposite is true if you handle it properly. Imagine telling the customer:

“That's no problem. It wasn't in the original scope and it will add £240 because I've got another electrician visit involved. It shouldn't affect the finish date. If you're happy with that, I'll add it to the variation and we'll get it done.”

Everybody knows where they stand. Compare that with doing it, saying nothing and presenting them with an unexpected £240 charge at the end. The first feels organised. The second feels like a surprise bill, even if the £240 itself was completely reasonable.

Get into the habit before the problem appears

Variation control is one of those things that feels unnecessary on the jobs where everything goes well. Then you get the one job where the customer remembers a conversation completely differently to you and suddenly you wish you'd written everything down. Build it into the process.

Keep the original scope and price with the job, record the change and new price, then get approval before carrying on.

It doesn't need to become complicated. It just needs to be consistent.

Every Install has a tool for this

The Variation / Additional Works Form is part of the Every Install Pro Toolkit. It gives you somewhere to record the additional work, price, effect on the programme and customer approval rather than letting changes disappear into texts, WhatsApp conversations and memory.

Use the Variation / Additional Works Form in Every Install Pro →

The Scope of Works Builder and Quote Checklist are also in the Price & Quote section of Pro. Getting the original scope right makes handling the changes much easier later.

Explore the Every Install Price & Quote tools →

This article provides general business information rather than legal advice. Consumer and contract rights can depend on the individual agreement and circumstances.