Guide · 5 min read
How to price a variation for a UK builder.
A fair variation price is built the same way as your estimate, and it is agreed before the work starts.
Start from your rate cards
Use the same labour rates, plant rates and material prices as your original estimate. Clients accept a variation more readily when they can see it follows the logic of the contract price.
Price the four parts
- Labour: hours multiplied by your agreed rate.
- Plant and equipment: hire or time-based rates.
- Materials: the supplier price, plus any allowance you normally apply.
- Subcontractors: their quote, plus the margin you normally add.
Don't forget the programme
An extra day on site costs more than the labour for that day. It carries site overheads such as welfare, supervision and hire, and it can push back other trades. Price the time as well as the work, and show the programme effect on the variation.
Add overheads and profit openly
Show overheads and profit as a line of their own, using the percentage from your estimate. Hidden margins cause disputes. Clients trust a breakdown they can read.
When the scope is unclear
If you cannot price the work yet, agree a day-work rate or a provisional sum before starting. Write down the rate, the reason for the uncertainty, and when you will confirm the final figure.
A worked example
A drain run found under a slab might be priced like this. The figures are illustrative.
| Line | Amount |
|---|---|
| Labour, 16 hours | £720 |
| Plant hire | £380 |
| Materials | £540 |
| Drainage subcontractor | £420 |
| Overheads and profit | £340 |
| Variation total | £2,400 |
The total goes with two extra days on the programme, shown on the same record.
Common mistakes
- Pricing after the work is done.
- Leaving out the programme effect.
- Sending one lump sum with no breakdown.
- Starting before the client has agreed the change.
Related guides
- Variation guideHow to stop extra work going unpriced, unsigned and unbilled. A practical guide for UK builders and remodellers.
- What is a variationWhat counts as a variation in a UK building contract, the common types, what usually isn't one, and why the paperwork matters.
- Extra work on siteA six-step checklist for UK builders when a client asks for extra work on site: pause, price, get it signed, then start.
- Variation or change orderVariation or change order: what the terms mean in UK building contracts, what matters more than the name, and how to record every change.
- Avoiding unpaid extrasFive habits that stop unpaid extras on a building job: site logs, photos, same-day pricing, written confirmation and billing in every application.