Victorian Renovations: Keep Cost-Plus Investigation Separate From the Main Build

SEPARATE INVESTIGATION FROM THE MAIN BUILDVictoria cost-plus renovation contract checks

Unknown conditions do not settle the contract model

A builder may say a renovation cannot be priced until the walls are opened. That is a reason to define investigation carefully, not a reason to accept unlimited reimbursable work across the whole project. Consumer Affairs Victoria describes restrictions on cost-plus domestic building contracts and a limited renovation investigation exception. Ask a building lawyer to identify the lawful basis before signing. The commercial decision is how to buy enough information to price the remaining work without letting a small exploratory appointment become the main construction contract by accident.

Establish the legal boundary before comparing the fee

CAV guidance says a cost-plus method cannot be used for a contract below its stated million-dollar threshold, subject to the investigation exception it describes. The Victorian Government’s contract guide explains that a cost-plus final price is unknown at signing. Do not assume a low builder’s percentage makes the arrangement acceptable. Have the lawyer confirm the current threshold, statutory wording, contract date and actual scope, especially where several related appointments are proposed. Do not split one project artificially to manufacture an exception.

Describe the questions that investigation must answer

Prepare a brief identifying the uncertain items: for example, the condition of an existing connection, access to a concealed junction or the extent of a suspected defect. Ask the relevant designer or engineer to specify what information is needed and the safest investigation method. The brief should identify what can be opened, what must remain protected, what temporary making-good is included and who receives the findings. These are recommended scope controls, not a claim that every renovation needs identical exploratory work. Keep asbestos and other hazards within the appropriate specialist process.

Put an estimate and a review point around the investigation

The CAV contract guidance says investigative renovation work must carry a fair and reasonable estimate of what the builder is likely to receive, with a fixed-price contract for the remaining work. Ask for the assumptions behind that estimate, labour rates, subcontractor charging, material treatment and agreed fee basis. Discuss a review point with the lawyer so additional investigation is assessed before expenditure expands. A budget allowance is not automatically a binding ceiling, so make the intended commercial protection explicit in the contract rather than relying on a spreadsheet note.

Keep cost evidence usable while the work is exposed

Ask the quantity surveyor what records are needed to reconcile labour, materials, subcontractor charges and any fee. Agree how invoices, time records and photographs will be presented and how credits or returned materials will be recognised. Identify who can authorise a scope change. These controls help you understand a reimbursable account; they do not replace statutory rights or turn an unlawful contract into a lawful one. Preserve findings from the investigation so later tenderers can price the same known conditions rather than each adding a different uncertainty allowance.

Use a clear stop between discovery and construction

Suppose a proposed renovation needs a small opening-up package before the structural connection can be designed. The builder investigates, the engineer records the condition and the designer revises the detail. Before permanent reconstruction proceeds, reconcile the investigation account and obtain the properly documented price for the remaining scope. Do not let the team continue simply because trades are already on site. Ask the lawyer how the handover, safety responsibilities and temporary protection should operate while the next contract is negotiated. Programme that pause honestly instead of hiding it inside an optimistic construction start.

TPC deal lens: compare the whole exposure

Compare offers using the investigation estimate, professional design work, temporary protection, remaining building price and contingency for unresolved items. A cheaper initial appointment can leave more uncertainty in the next stage. Have the quantity surveyor identify what has actually become known and which allowances still need evidence. Keep contract-model advice separate from the cost comparison: one establishes whether the arrangement is suitable and lawful; the other tests whether the resulting scope is affordable. Neither a standard form nor a familiar builder’s name removes the need to read the actual terms.

Key takeaway

Investigative work should produce information that supports a defined next decision. You are not expected to interpret cost-plus exceptions yourself. Use the building lawyer for the legal boundary and the quantity surveyor for the estimate and reconciliation. Your turn: what document will stop the investigation appointment from rolling into permanent works before the remaining price and scope have been agreed?

Your practical decision checklist

1. Get legal confirmation of the permitted pricing method.
2. Define the questions, access and limits of investigative work.
3. Agree cost evidence, estimate assumptions and authorisation of extra investigation.
4. Reconcile the findings before entering the contract for the remaining works.

Image credit: Troy Mortier / Unsplash. Illustrative photograph. Source · Licence Cropped.

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