Sydney renovation budget for 160 m² multifamily: where are the real cost risks?

LightStory

Construction professional
Established
I need to settle the contingency before the tender scope goes out, and the choice is between retaining the current design or simplifying it while changes are still cheap.

The working budget is A$575,100 for a 160 m² small multifamily in Sydney. The planned work covers the kitchens and wet areas, new finishes, painting, an electrical review and some energy improvements. There is no planned addition, but concealed damage or remedial work could still affect the cost.

I want contractors to be explicit about access, demolition, making good, temporary services and anything they expect another trade to provide. The electrical item is particularly unclear: should the tender include only testing, specified repairs or an allowance for wider replacement? Permit timing, long-lead materials and moving trades between units also need to be reflected in the programme.

Which questions would you put to the surveyor before tender, and which exclusions would you insist contractors price separately?
 
I wouldn’t set contingency from floor area alone. First split the A$575,100 into defined work, provisional allowances and genuinely unknown conditions. Ask each contractor whether demolition, disposal, temporary services, making good after plumbing or electrical work, and protection of retained areas are included. Those boundaries often matter more than the headline price.
 
How many kitchens and bathrooms are involved, and will any units remain occupied? Those two facts could change the sequencing considerably. Also establish whether wet areas are stacked and whether pipework is accessible from below. If access requires opening finished ceilings or common areas, a seemingly straightforward plumbing allowance can spread into several other trades.
 
If moisture is not investigated first, the tender may be pricing the wrong job. I would look for current or historic leaks, failed waterproofing, damp near windows and staining that keeps returning, then ask how each bidder would treat damaged material uncovered during strip-out.

Contract exclusions still matter, but they are easier to compare once the likely condition of the building is understood. For example, opening a wet-area wall may reveal deterioration that adds carpentry and making-good work as well as plumbing. Avoiding an addition does not remove that risk.
 
Fair point. I’d investigate moisture and access before trying to negotiate a neat fixed figure. The electrical wording also needs tightening: does “checks” mean inspection only, identified repairs, replacement of fittings, or broader upgrades? Contractors cannot price consistently if that remains vague, so the apparent spread between tenders may just reflect different assumptions.
 
For contingency, I’d carry more while those questions remain open and reduce it only when access has been inspected and exclusions reconciled. Keep that reserve outside the finishes allowance; otherwise upgrades to tiles or appliances quietly consume money intended for hidden conditions. A simple tender comparison table with identical scope lines should expose omissions without pretending every quote is directly comparable.
 
Material lead times and permit timing need their own sequence, not just notes in the budget. Ask contractors which selections must be locked before demolition, what can be substituted without redesign, and which activities depend on approvals. I would also identify a minimum viable finish package now, so there is a pre-agreed simplification route rather than rushed cuts after work starts.
 
One more question for the surveyor: which walls, penetrations and services cannot be confirmed without opening up? List those areas separately and consider targeted investigation before the main contract, where practical. The aim is not to discover everything in advance—it is to know which assumptions could trigger several trades at once. Plumbing access plus ceiling repairs plus repainting is a different risk from one missing light fitting.
 
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