Argue changed conditions, not just changed quantities
Your contract rates were priced for set conditions, so a change done in harder conditions can justify a higher rate. Quantity times rate is only the start: say what changed and show why the rate should move.
Updated: . By Jack Butler-Kettle, Construction Claims Consultant.
Why it matters
A rate in your priced bills was built for a set of conditions: ground floor, clear access, summer, in sequence, in bulk. Your main contractor then applies it to work on the fifth floor, in winter, in a live building. It calls that the contract rate. It is, but for different work.
The rate only gets adjusted if you say the conditions changed and show how, with the diary and the photographs to prove it. Quantity times rate is easy to check and easy to accept, which is why your main contractor proposes it. The adjustment is where the real cost of the change sits.
How to do it
- Write down, for each variation, the conditions the contract rate assumed: location, access, sequence, season, quantity and working hours.
- Compare those with the conditions the changed work was actually done in, and list every difference.
- Price each difference separately, such as extra handling, lower output, standing time or out-of-hours premiums, with the record that shows it.
- Present the result as the contract rate plus named adjustments, not as a new rate.
Example
Illustrative example. The scenario and figures are invented.
The facts
A subcontractor's contract rate for blockwork is £62 a square metre, priced for open ground-floor work in sequence. A variation adds 150 square metres of blockwork in an occupied basement plant room. The work is after hours, with materials carried by hand through a single door.
What happens
- The commercial manager lists the changed conditions: hand distribution, restricted hours and working around live plant.
- The diary shows output of 9 square metres a day, against 18 on the contract work. The hand distribution added 30 hours.
- The valuation is the £62 rate, plus £28 a square metre for halved output and £1,050 for distribution.
Basement blockwork valuation
| Item | Amount |
|---|---|
| 150 square metres at contract rate, £62 | £9,300 |
| Output adjustment, 150 at £28 | £4,200 |
| Hand distribution, 30 hours at £35 | £1,050 |
| Total | £14,550 |
The outcome
The main contractor's surveyor agrees £14,000 after checking the diary. Quantity times rate would have paid £9,300 for work that cost £13,000 to do.
To have this done for you, see our Variation Claim service.