Can you vary a contract without a variation clause?
Only by agreement, because without a variation clause neither side can order a change on its own.
Updated: . By Jack Butler-Kettle, Construction Claims Consultant.
The answer
A variation clause is what lets one party order a change. It also makes the other party carry the change out, for a value set by the contract's rules. Without one, the contract covers the agreed scope and nothing more. Extra work can still happen, but each item is a new agreement. Ideally it is in writing before the work starts, and says what is to be done, for how much or on what basis, and when. If you do work at the other side's request with no agreed price, you can usually recover a reasonable value for it. But proving the request and the value is much harder than pointing to an instruction and a rate. The standard forms all have a variation clause. The gap shows up on bespoke and short-form contracts, letters of intent and purchase orders. Check before you price the first change, not after.
Example
Illustrative example. The scenario and figures are invented.
The facts
A joinery subcontractor's purchase order covers £48,000 of joinery, with no terms beyond the price and the dates. The main contractor's site manager asks for a further £6,000 of skirting, and there is no variation clause to instruct it under.
What happens
- The subcontractor writes a one-page agreement for the skirting, with its price and delivery date.
- Someone with authority on each side signs it before the material is ordered.
- Without that agreement, the £6,000 would be a reasonable-value claim resting on emails and a request nobody signed.
The outcome
The skirting is added at £6,000 under a signed agreement, not argued over later as a reasonable-value claim.
Variation Claim gets changes agreed by conversation paid, starting from the evidence that they were agreed.