Imagine you’re reading a building contract for the first time. Somewhere in the schedule there’s a line for tapware, another for floor tiles and a sum set aside for excavation. A few weeks into the build, a figure on an invoice changes, and the builder calls it a variation. You thought it was an allowance. Your builder thinks it’s an upgrade. A friend says it’s the contract’s fault.

Everybody is using the same words and meaning different things.

An allowance and a variation are not interchangeable labels for any extra charge. Understanding what remains undecided helps you ask better questions before signing and keep clearer records during construction. This guide uses the Consumer Affairs Victoria terminology and offers a practical way to track uncertain items. It doesn’t give advice on any particular contract dispute, and it can’t replace advice on your own situation.

Prime Cost Items: Unresolved Selections

Consumer Affairs Victoria describes prime cost items as fixtures and fittings listed in the contract but not specifically identified and costed, because the make, model or exact price hasn’t been determined or agreed. Taps, tiles and appliances are examples.

The key point is that the amount in the contract is an estimate. It isn’t confirmation that any later selection will fit within it. If you choose a tap you love and it costs more than the allowance, the difference is the kind of question you want answered before you fall in love with it, not after.

Where possible, resolve selections before signing. When you can’t, ask the builder to identify:

1. The product the allowance is based on.

2. The quantity included.

3. The allowance basis, meaning what the figure does and doesn’t cover.

4. Any related installation work.

Then check whether a different selection affects anything else in the design. A larger oven might change the cabinetry. A different basin might change the plumbing connections. A heavier tile might affect the floor preparation. Record the decision in the appropriate documents, because a showroom conversation alone doesn’t tell everyone which item is to be supplied.

Provisional Sums: Work That Cannot Be Exactly Priced

Provisional sums are a different kind of uncertainty. Consumer Affairs Victoria describes provisional sum items as possible additional work where the builder can’t give an exact price at signing and can only make a reasonable estimate.

Its excavation example is a useful one: costs may rise if rock wasn’t established by the soil report. Nobody has chosen anything wrong. The ground simply hasn’t revealed what’s in it yet. That’s quite different from leaving an appliance model undecided, even though both introduce pricing uncertainty.

So ask what information supports the estimate, and what investigation could reduce the uncertainty. Identify the quantities, the boundaries of the work and any related exclusions.

This matters most when you’re comparing tenders. If different tenders use different allowances for the same work, request the basis rather than treating the lowest figure as evidence of a lower final cost. A low number may simply reflect an optimistic allowance. Keep the underlying scope visible when you compare offers, so you’re comparing like with like.

Variations: Changes to the Agreed Work

Variations are changes to the work itself. Consumer Affairs Victoria explains that variations include changes agreed by owner and builder, and changes ordered by an authorised person after signing and commencement.

Its guidance sets out a written variation process, including the details of the change, its cost and its effects on the total price and the completion date. It also describes limited exceptions. The exact legal position depends on the circumstances, so obtain advice if there’s disagreement.

As a practical discipline, request a written record for every proposed change, even when someone suggests a small change can be handled informally. For each one, identify:

• Why the change is needed.

• Which documents change as a result.

• Whether any approvals are affected.

Two cautions are worth keeping in mind. Don’t describe all unexpected conditions as automatically payable variations. And don’t assume every cost change is solely a homeowner selection issue. Where responsibility sits depends on the contract and the circumstances, and treating everything as one category tends to create arguments later.

Keep Three Separate Registers

The simplest way to stay on top of all this is to stop mixing the categories. Keep three separate lists, even if they’re only a page each in a notebook or spreadsheet:

1. Selections. Prime cost items you still need to choose, with the product, price and date decided.

2. Provisional work. Items that can’t yet be priced exactly, with what investigation or information would settle them.

3. Scope changes. Proposed and agreed variations, with the reason, price effect and programme effect.

A practical checklist to go with them:

1. Request the basis and inclusions of every allowance before signing.

2. Record the proposed change, price effect and programme effect before agreeing.

3. Retain notices, correspondence and invoices relevant to adjusted items.

4. Keep the signed documents, selection decisions and cost records together.

Keep Evidence and Reduce Uncertainty Early

Consumer Affairs Victoria recommends obtaining invoices, receipts or other documents showing the cost of prime cost and provisional sum items. Keep these with the signed documents and your selection decisions, so adjustments can be understood later. When someone asks in six months why a figure changed, the answer should be in a folder, not in anyone’s memory.

If a charge seems inconsistent with the scope or the process, seek independent advice rather than relying on a general web explanation to decide your payment rights. This article, and any other, can help you ask better questions, but it can’t tell you what you owe.

Reducing uncertainty early is the other half of the job. Every selection made before signing is one less open item. Every investigation completed before pricing, such as a soil test or a site survey, is one less provisional estimate that could move.

Start with Clear Scope

Explore the EJN Build custom home or renovation service page once your selection and investigation questions are organised. Read “Custom Home Tender Inclusions” to compare allowances across offers, and “Residential Site Costs” for the investigations behind ground-related estimates. The aim is clear scope and traceable decisions, not a promise that every uncertainty can be removed. Some uncertainty is simply part of building on real ground with real products.

Questions Before Your Next Step

Is choosing a more expensive tap always a variation?
Not necessarily. It may involve adjusting an existing prime cost item, and associated design or work changes may need separate treatment. Check the item, scope and applicable contract process rather than using one label for everything.

Can I approve changes by text message alone?
Don’t assume a casual message meets the applicable process. Consumer Affairs Victoria recommends written, signed changes and explains variation notice requirements and exceptions. Seek specific advice if the process is unclear.

Related Reading:

• Custom New Homes in South East Melbourne

• Renovate or Extend: Choose the Right Change

• Custom Home Tender Inclusions: Compare the Whole Scope

• Residential Site Costs: Questions Before You Build

Official References:

• Changing a Major Domestic Building Contract: Checklist | Consumer Affairs Victoria

General Victorian information, not project-specific legal, planning or technical advice. Confirm current requirements with the relevant authority and appointed professionals.

At EJN Build, we help Victorian homeowners define scope clearly from the start, so uncertain items are named, tracked and understood rather than discovered on an invoice. If you’re planning a custom home or renovation, discuss your project with EJN Build.