How variations affect the job

An approved variation is not just an extra invoice. It changes the contract, and four things move with it.

1. The contract sum

The variation value is added to (or deducted from) the contract price.

That matters more than it sounds, because progress claims are percentages of the contract sum. See Contract stages.

Worked example

The Hendricks contract at $221,380, with two approved variations:

	Value
Original contract	$221,380
VO 04 — tapware above PC allowance	+$862
VO 05 — delete rear deck	−$7,381
Revised contract sum	$214,861

Now look at what that does to a stage claim. Fixing is 25% of the contract:

	Claim at fixing
On the original contract	$55,345
On the revised contract	$53,715

A $1,630 difference on one stage, from two variations. Claiming against the original figure over-claims; not raising the credit at all would have over-claimed by more. Both are the kind of error that surfaces at the final claim, when it is least convenient.

2. What you can claim

Approved variations become claimable. Depending on your contract, either as part of the next progress claim, or separately.

Unapproved variations are not claimable. That is the practical reason to chase approvals — see Getting client approval.

3. Your orders

A variation that changes the work usually changes what you need to buy.

Variation	Order consequence
Client upgrades the tapware	Revise or replace the plumbing order
Client deletes the deck	Void the decking order
Rock in the excavation	New order for rock removal
Design change to the roof	Void the old order, raise a new one

Nothing does this automatically. The variation handles the client side; the supplier side is a separate action, and forgetting it is how you end up paying for a deck you credited.

Two sides to every change

A variation is the client side of a change. The supplier side is an order. Raising one without the other leaves your committed cost wrong in one direction or the other — and a credit variation with no voided order means you have paid for something you are no longer being paid for.

4. The programme

Extension of time (days) on the variation extends the contract completion date.

Claim it at the time. An extension cannot sensibly be claimed after the completion date has passed, and a builder who has claimed the money but not the time has accepted the original date for a larger scope.

What to do when a variation is approved

A five-point checklist:

1. Tick Accepted by client.
2. Check the revised contract sum is what you expect.
3. Raise, revise or void the affected purchase orders.
4. Confirm the extension of time is recorded.
5. Add the work to the schedule, if it is significant.

Steps three and five are the ones that get missed under pressure, and they are the ones that cost money.

Variations and the estimate

Variations do not change the original Bill of Quantities — the estimate stays as a record of what was priced at contract.

If you want the BOQ to reflect the current scope, add items for the varied work. Most builders do not, preferring to keep the contract estimate clean and read the variations alongside it. Either is defensible; be consistent, because mixing the two approaches on one job makes the cost reports very hard to read.