What is a variation in construction? A plain-English guide for subcontractors
What counts as a variation, who can direct one, why written notice matters, and the records that get it paid. For Australian subcontractors.
Every subcontractor does variations. Not every subcontractor gets paid for them. The difference is usually not the work, it's the paperwork: who asked, whether it was in scope, whether notice was given in time, and whether there's a record when the claim goes in.
The short definition
A variation is a change to the work you agreed to do under your contract. It can be:
- Extra work: "Add two more GPOs in the kitchen."
- Different work: "Move the switchboard from the garage to the laundry."
- Less work: "We're deleting the outdoor lighting." (Yes, these are variations too, and they reduce the contract price.)
- A change to how or when you do the work: a different sequence, working out of hours, or a change to access that adds time or cost.
The test is simple: is this in the scope I priced? If not, it's probably a variation.
Scope: the document that decides everything
Your subcontract will define your scope, usually through a scope of works, drawings, specifications, and a list of inclusions and exclusions. When a builder asks for something, the first question is always "is this in my scope?"
Exclusions are your friend. If your scope says "relocation of existing services excluded", then a request to relocate a switchboard is clearly extra. If the scope is vague ("all electrical works to complete the project"), you'll have a harder argument. That's worth knowing before you sign: a good scope with clear exclusions is the cheapest variation insurance there is.
Who can direct a variation?
Most subcontracts say only certain people can direct a variation: often the builder's project manager or a named representative. A site supervisor's verbal "just do it while you're there" may or may not count, depending on the wording.
In practice, most variations start as a verbal request on site. That's fine, as long as you record it straight away (who asked, what, when) and follow it up in writing, the way your contract requires. We go into this in detail in verbal instructions on site: how to stop doing extra work for free.
Written notice and time limits
This is the part that costs subcontractors the most money. Many subcontracts require you to give the builder written notice of a variation (or of a claim for extra time or money) within a set period, often a handful of business days from the instruction. Some say that if you miss the deadline, you lose the right to be paid for it. These are often called time bars.
Courts don't always enforce time bars strictly, and some states' security of payment laws affect how they apply. But arguing about it costs far more than the variation is worth. The practical rule: find the notice clause in every subcontract, and give written notice every time, on time.
A good written notice includes:
- A clear description of the change.
- Who instructed it, when, and how (verbal on site, email, revised drawing).
- Why it's outside your scope, referring to the contract clause or exclusion.
- A price, or an estimate if the final cost isn't known yet.
- Any impact on time.
- Photos or marked-up drawings.
Our guide on how to write a variation the builder will approve has a full checklist.
Pricing a variation
Your subcontract may say how variations are priced: using rates in the contract, using a schedule of rates, or at "reasonable rates" if none apply. If you've given the builder a rate card, use it. Consistency matters. A builder who sees the same labour rate and margin on every variation stops arguing about the rate and only checks the quantities.
Break it down: labour (hours × rate, by role), materials (with your agreed margin), plant or equipment hire, and any extra supervision or travel. Lump sums with no breakdown are the ones that get queried.
Approval and getting paid
An approved variation isn't money in the bank. It's the right to claim. You still include it in your progress claim (payment claim) under your contract. In Australia, each state and territory has a security of payment Act that sets rules for payment claims and gives you a fast-track adjudication process if you're not paid. Approved variations with a clear paper trail are far easier to claim, and to defend if it comes to that.
Unapproved variations can sometimes be claimed too, but they're much harder. This is why the record you make on day one matters so much.
The records that get variations paid
If you remember one thing from this guide, make it this. For every variation, you want:
- The instruction: who, what, when, and how.
- Evidence: photos before and after, marked-up drawings, messages.
- The scope check: the clause or exclusion that shows it's extra.
- The written notice, sent on time to the right person.
- The price, broken down from your rates.
- The approval (or the query, and your answer).
None of this is hard. It's just hard to do at 7am on site, with a builder waiting, when the crew is under pressure. That's where most variations leak: not in the argument at the end, but in the first ten minutes when nobody wrote anything down.
Making it easier
Whatever system you use, the key is making the first record effortless for the crew. A photo and a voice note sent straight away beats a perfect form filled in on Friday. Variation Capture is built around exactly that: the crew sends a photo or voice note, and it's checked against the contract, priced from your rate card, and drafted for your office to approve. See it in the demo.