Guide
How to write a variation
A variation is any change to the work after the contract or quote was agreed. Written well and signed before the work is done, it gets paid. Done on a handshake, it is the first thing argued about at the end.
Updated · General information, not legal advice. Check your contract, the official source and, if it matters, a lawyer.
What counts as a variation
Anything added, taken out or done differently from what was agreed: an extra power point, a different tile, a wall that has to come out, a fixture the client changed their mind about. Taking work out is a variation too (an omission), and it lowers the price.
It does not matter how small. A run of small unwritten extras is how a job that was quoted at a fair price ends up losing money.
Get it in writing, before you do the work
For home building work in New South Wales, NSW Fair Trading says variations must be in writing, attached to the contract and signed by both the owner and the builder or tradesperson (or their nominated supervisor or agent). Its consumer guidance says to put every variation in writing, no matter how small, because it can become vital if there is a dispute later.
There is a narrow exception. Where a variation is needed because someone is likely to be in danger or property damaged, there may not be time to write it up first, and the written variation can follow after the work. Other states have their own home building rules; check your regulator.
On commercial work and subcontracts, the contract decides how variations are directed, priced and approved. Read that clause before the job starts, not when the first change comes.
What to put in it
Variation checklist
- A variation number (V1, V2 and so on) and the date
- The job, the contract or quote it changes, and the client
- What is changing, in plain words, with drawings or photos if they help
- Why: client request, a site condition, a design change
- Who directed it, when, and any site instruction number
- The price: labour, materials and margin, or an omission credit
- Any extra time it adds to the job
- How it will be paid: with the next claim, or on its own invoice
- Space for the client or builder to sign and date their approval
If the work has to go ahead before it can be priced, for example when you cannot see what is behind a wall, say so: agree in writing that it will be priced on time and materials at your listed rates, and record the hours and materials as you go.
Notice periods in subcontracts
Many subcontracts say you must give written notice of a variation, or of a claim for extra time, within a set number of days of being directed. Miss it and the contract may say you lose the right to be paid for it. Find the number in your contract, and send notice in writing the same day you are directed, even if the price comes later.
Pricing it fairly
Price a variation the way you price the original job: materials at current prices, labour at your charge-out rate, and margin. If your contract has a schedule of rates for variations, use it. Show the client enough of the breakdown to see it is fair; a single unexplained number invites an argument.
Remember the knock-on costs: extra trips, a return visit for another trade, waste, and time the change adds to work you have already priced.
Keep a register
On anything bigger than a few days, keep a list of every variation: its number, status (draft, sent, approved, rejected), value and date. It is your record at the end of the job, and the first thing a builder or client will ask for if the final account is disputed.
Variations in the app
In Crewzy, bigger work goes in a project, and its Variations tab is the register. A variation has what changes, the reason, who directed it and when, a site instruction number and any extension of time, with lines priced from your price list. Send it like a quote: the client or builder approves it online with their name and signature. Approval adds it to the contract value and the budget, and it is claimed on its own line. A worker can raise one from site on their phone, with photos and the client's signature, without seeing prices. You can set a notice period, and late ones are flagged. Projects and variations are on the Connected and Unlimited plans. See Variations.
Common questions
Does a variation have to be in writing?
For home building work in NSW, yes: NSW Fair Trading says variations must be in writing and signed by both parties, except where urgent work is needed to prevent danger or damage. Other states and commercial contracts have their own rules, so check your contract and regulator.
Should I start the work before the variation is approved?
Not unless it is urgent or your contract allows it. Get the variation priced and approved in writing first, or at least agree in writing how it will be priced.
Sources
Official pages this guide relies on, read on 23 October 2026. Rules change; check them before you rely on anything here.