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AE INDEX
Melbourne Renovation Cost Index
Renovation costs
Williamstown 3016

What a renovation
costs in Williamstown

Williamstown is one of Melbourne’s oldest settlements, and it builds like it — Victorian cottages on small allotments, extensive heritage precincts, coastal salt exposure, and a maritime industrial history that shows up in the soil.

Indicative ranges

Rear extension
$335k – $455k

40 m², mid finish, one new wet area, heritage

Second storey
$580k – $785k

60 m², mid finish, one new wet area

Full renovation
$1135k – $1530k

150 m² internal, high finish, kitchen and bathroom

Rates: Archicentre Australia CostGuide 2026 · GST inclusive
Site adjustments for Williamstown conditions: AE Index

What drives cost here

Extensive heritage coverage

Hobsons Bay maintains significant precincts across the older streets near the point. Coverage is among the most comprehensive in the western suburbs, and it shapes both design and timeline.

Small original allotments

The oldest parts were subdivided long before cars. Narrow blocks and limited access mean materials frequently move by hand or by crane.

Coastal exposure

Salt and wind drive material selection — marine-grade fixings and corrosion-resistant hardware. A specification premium rather than a labour one.

Maritime industrial history

Former port and industrial land carries contamination potential in defined pockets. A soil report early is considerably cheaper than a discovery during excavation.

Typical Williamstown projects

ProjectWhy it costs what it doesRange
Rear extension to a Victorian cottageSmall footprint, restricted access, heritage assessment on the design.$335k – $455k
Second storey behind a retained facadeOriginal cottage footings usually need substantial upgrading to carry a new floor.$490k – $665k
Whole-house renovationServices replacement plus restoration of original fabric in a heritage precinct.$925k – $1255k
Bathroom onlyBelow our minimum — referred to a single trade.$28k – $50k
A note on premium suburbs. Building in Williamstown does not cost more per square metre because of the postcode. It costs more because projects here are larger and specified to a higher finish — and finish level is the single biggest variable in any renovation budget. Our location adjustment reflects site constraints and labour rates, not what the street is worth.
Minimum project size. AE Index works on structural renovations and extensions from $150,000. Smaller jobs and single-trade work are referred on rather than quoted.
Your project, not an average

Two minutes, no phone call

Williamstown is already selected. Answer eight questions and you will see an indicative range, the full calculation behind it, and what to ask any builder quoting the job.

Common questions

Is most of Williamstown heritage protected?

A significant proportion of the older areas near the point, yes. Hobsons Bay maintains extensive precincts reflecting the suburb’s age. Check the planning property report for your address before briefing a designer.

Does coastal location add to renovation cost in Williamstown?

Through material specification. Salt exposure calls for marine-grade fixings, corrosion-resistant hardware and more robust external finishes, which published square-metre rates do not distinguish.

Should I be concerned about contaminated land in Williamstown?

In defined pockets with maritime or industrial history, it is worth checking rather than assuming. A soil report early lets a builder price the work accurately instead of loading the quote with contingency.

What is not included in these ranges?

Landscaping and external works, appliances, furniture and window furnishings, council planning application fees, driveway reinstatement, and anything found once walls are opened. Design fees, engineering, building surveyor, permit levy and energy assessment are included.

Related

When you are ready to build

AE Index is not a building company. When a project is ready to be priced properly, we pass it to a builder from our verified network — who will walk the site, inspect what is under the floor, and put a fixed price in writing. We are paid a fee by them on work that proceeds, and you are under no obligation to use them.

  • Current domestic builder registration, confirmed with the Victorian Building Authority
  • Domestic building insurance current and sighted
  • Two completed projects contacted directly — not supplied testimonials
  • Fixed-price contracts with a written variations policy
  • Re-checked annually, and removed from the network on any lapse

Last updated 28 July 2026

AE Index publishes indicative cost data for Melbourne residential renovation. Estimates are budget-setting figures, not quotes, and assume a standard site with no undisclosed structural, drainage or contamination issues. Square-metre rates are drawn from the Archicentre Australia CostGuide 2026, an independently published Australian cost guide, and are GST inclusive. Site adjustments are AE Index's own and are labelled wherever they appear. AE Index refers projects to a builder from its verified network and receives a fee on work that proceeds.