Where variations leak
Disputed variations rarely fail because the entitlement was wrong. They fail because the evidence supporting the entitlement was assembled three months after the event, by a QS who was not on site, from emails that did not name the right things. The contract says the contractor can recover; the evidence says they cannot prove it.
The cure is a short evidence chain that runs at the moment the variation is identified - not later. Four links, each cheap to produce, each defensible in isolation.
The four links
- Instruction - written reference to what was instructed, by whom, when. Verbal-on-site is insufficient: the next step is to confirm the verbal in writing within 24 hours.
- Basis - the contract clause or specification reference that makes the change a variation rather than scope.
- Narrative - one paragraph, plain English, on what was done and why. Avoids legalese; written for the buyer's project director, not the dispute lawyer.
- Sign-off - the named approver on the client side, the date, and the version of the variation register at the time of approval. If the buyer challenges later, the audit trail shows what they signed.
Why this beats the heroic-spreadsheet approach
The reason variation registers fail under pressure is that they reward late-stage assembly. A QS opens a spreadsheet, hunts down the instruction, hunts down the contract clause, writes the narrative, and chases the approver. Anything that takes more than five minutes per variation does not happen on a busy week.
An evidence chain produced at the moment of identification - by whoever raised the variation - distributes the work across the people who already have the context. The QS becomes an auditor, not a reconstructor.
What this looks like in BuiltAI
The Commercial Control Kit ships a variation register where each row enforces the four-link structure at create. The site-team-facing form takes 90 seconds to fill in and writes the audit row for the variation log automatically. Approvers see a queue with the basis and narrative inline; sign-off is one click.