Variations guide
How to price and approve building variations
A practical written process for changes, hidden conditions and extra work after the original quote is agreed.
Short answer
Record the change, price the cost and time effect, then get written approval before the extra work starts. Keep the agreed variation with the quote and update the running total.
- 1
Stop and record
Photograph the issue or record the requested change before covering it up.
- 2
Describe the change
State what is added, omitted or altered, including any effect on earlier work.
- 3
Price the effect
Show labour, materials, plant, subcontractors, overhead and profit. Credit omitted work where relevant.
- 4
State the programme effect
Give the extra time or explain when it can be confirmed.
- 5
Get written approval
Record the client’s approval and date before starting, except for genuine safety action.
- 6
Update the job records
Add the approved value and time to the running contract total and programme.
Variation price build-up
Labour: hours × your charge-out rate
Materials: quantity × cost, including waste
Plant and access
Subcontractors
Overheads and profit
Less any omitted work
Work agreed at a client’s home
Consumer cancellation rules may apply when a client agrees extra work at home. Do not rely on a general waiver. Check what documents and approval you need before starting.
Sources and further reading
This guide is general information for UK building businesses. It is not legal, contractual or tax advice. Your contract and the facts of the job take priority.