Guide

Variations and extras: how to get paid for work outside the quote

Last reviewed 12 September 2026

Almost every job changes. The money is lost not in the change but in the twenty seconds where somebody says "while you are here" and nobody writes anything down.

Ask any experienced trade where their margin goes and the answer is rarely the original price. It is the small additions: the extra socket, the second coat, the bit of making good, the door that had to come off. Individually none of them is worth an argument. Together they are the profit on the job.

Why extras go unpaid

Three reasons, and all three are about timing rather than goodwill. The work is agreed verbally in the middle of doing something else. It is priced afterwards, when the customer has already had the benefit and the number feels like a penalty. And it appears for the first time on the final invoice, next to the figure they were expecting, which turns a fair charge into a shock.

The process, in four steps

This takes two minutes on site and it works because it happens before the work, not after.

Stop and name it. "That is outside what I quoted, so let me price it for you."
Put it in writing, at once. A message from your phone is enough: what the work is, what it costs, how many days it adds, and that the original price and programme are otherwise unchanged.
Get an answer in writing before starting. "Yes, go ahead" in a text message is a written instruction, and it is all you need.
Bill it separately, itemised on the invoice as an agreed variation with the date it was approved.

The wording that works

Keep it short and neutral. "Following what we found under the bath today: the joist ends are wet rotted and need cutting out and sistering before the new floor goes down. That is 1.5 days plus about 180 pounds of timber and fixings, so 620 pounds plus VAT, and it adds two days to the finish date. Happy to proceed on your confirmation." Nothing in that sentence is arguable, and it arrives before the money is spent.

Small extras, and the rule of thumb

Not every five-minute favour deserves a variation notice, and a trade who prices every one of them is exhausting to employ. Set yourself a threshold, for instance anything over half an hour or over 50 pounds, and be generous below it and disciplined above it. The generosity below the line is what buys you the credibility above it.

When the customer changes their mind

A change of specification after work has started can cost far more than the difference in materials, because it may mean undoing something finished. Price the abortive work explicitly and say so: "The tiles are already fixed, so changing them now means removing and disposing of them and re-preparing the wall, which is 340 pounds on top of the difference in the tile price." A customer who understands the reason accepts the number.

Provisional sums and prime cost sums

Where you know an item is coming but cannot price it yet, carry a provisional sum in the quotation with a stated basis, and say clearly that it will be adjusted against the actual cost once the scope is known. It gives the customer a realistic total from day one and gives you a legitimate route to the real figure without it feeling like an extra.

On commercial contracts

Follow the contract's own variation procedure exactly, including who is allowed to instruct a change and in what form. A verbal instruction from somebody without authority is a very common way to end up doing work that nobody will certify. If you are told to proceed verbally, confirm it in writing the same day and ask for the formal instruction, then keep both.

Record as you go

Photograph what you found, before you fix it. Note the date and the person who approved the change. Keep the approval message. Six months later, on the one job in twenty that turns difficult, that folder is the difference between being paid and being told it was included.

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This guide is general information for UK trades, written by the BidReady team. It is not legal, tax or financial advice. Rules change and individual circumstances differ, so take professional advice before acting on anything that matters.