A variation in construction is any work a subcontractor or builder carries out that falls outside the scope originally priced and contracted — extra work, a design change, or something unforeseen (like hitting rock) that the client or head contractor asks for or agrees to on site. It has to be formally agreed and, once approved, it is billed separately from the original contract sum.
“Variation” and “change order” mean the same thing — see below for the terminology split. This page explains what counts, how a variation gets approved, and the one thing that actually decides whether you get paid for it: whether it makes it onto your next progress claim.
This is general information, not legal or contractual advice. What your contract requires for notifying and approving variations differs by contract and by state, so always check yours.
Variation vs change order: is there a difference?
No — they are the same thing described with different regional terms. “Variation” is the more common term in Australian and New Zealand construction contracts. “Change order” is the more common term in North American usage. Both describe agreed work added to, or changed from, the original contract scope.
Examples of construction variations
- Extra work the client asked for on site. Additional power points, a fixture upgrade, an extra section of fencing — anything requested beyond the original quote.
- Unforeseen ground conditions. Rock, contaminated soil, or existing services nobody knew were there when the job was priced.
- A design change. The architect or head contractor changes a detail after work has started.
- Upgraded materials or finishes. The client decides mid-job they want a better spec than what was originally quoted.
Verbal vs written variations
A verbal instruction can still be a genuine variation, but it is far harder to prove and to bill later once the work is covered up and memories fade. See our guide on getting paid for verbal variations for how to protect yourself when there is nothing in writing.
How a variation gets approved and billed
The loop that actually gets you paid is simple: the work is agreed by whoever has authority, you record it with proof on the day, and it lands on your next progress claim before the client’s billing cut-off. Miss that cut-off and, at best, payment waits a month — at worst, it gets forgotten entirely. See our guide on how to track site variations so every one gets billed for the full system.
Why proof matters
A variation being genuine is not the same as a variation being provable. Once the work is buried, backfilled, or built over, the only thing left is your record of it — a dated photo, who approved it, and the amount. No proof, no claim.
Track every variation automatically
This is exactly the problem we built Variation Tracker to solve:
- 60-second capture. Log a variation from your phone before you leave site: a title, the amount, done.
- Photo evidence. Attach a dated photo to every variation, so you have proof even after the work is covered up.
- Billing-date reminders. It tracks each client’s monthly billing date and reminds you before every unclaimed variation slips off the progress claim.
It is built for one-person and small crews, at $29 a month for two users. There is a free 30-day trial with no credit card required.
Frequently asked questions
What is a variation in construction?
It is any work outside the scope your contract originally priced — extra work the client asked for, a design change, or something unforeseen on site like hitting rock. Once it is agreed, it is priced and billed separately from your original contract sum.
What is the difference between a variation and a change order?
There is no practical difference — they describe the same thing: agreed work added to or changed from the original contract scope. "Variation" is the more common term in Australian and NZ construction contracts; "change order" is more common in North American usage.
Does a variation have to be in writing to be valid?
Most contracts require it, or at least require written notice within a set time. A verbal instruction can still be genuine, but it is far harder to prove and to bill later — see our guide on verbal variations for how to protect yourself when it stays verbal.
Who approves a construction variation?
Usually whoever has authority under your contract — often the head contractor, principal, or their superintendent/certifier. On smaller jobs it may just be the client. Check who is actually authorised to approve extras before relying on someone else's say-so.
How do I get a variation approved and paid?
Record what the extra work is, get it agreed by whoever has authority, note the amount and a dated photo, and make sure it is on your next progress claim before the client's billing cut-off. Missing that cut-off is the single most common reason variations never get paid.
What is a time bar in a construction contract?
A time bar is a contract clause that requires you to notify a variation (or claim) within a set number of days, or lose your right to be paid for it, even if the work was genuinely agreed. Always check your contract's notice period, not just its payment terms.
This page is general information, not legal or contractual advice. What your contract requires for variations differs by contract and by state. Check your contract and seek professional advice on any specific claim. Last reviewed August 2026.