Home Extension in Perth.Know what it should cost in Perth.
Tailored to the Perth, WA market — local pricing adjustment applied automatically. A few quick questions, no obligation.
A typical home extension in Perth costs between $99,750 and $336,000 in 2026, with most projects landing around $189,000.
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Where is the project?
Enter your postcode so we can apply local pricing.
- LocationPerth
- What type of extension?Ground-floor rear extension
- Approximate extension size (m²)40 m²
- What finish level are you planning?Standard
- When are you hoping to start?In 3–6 months
What goes into the number.
We start from a per-m² extension rate, scale by extension type, finish and site complexity, then add fixed inclusions like new bathrooms or kitchens.
- Extension size in square metres and whether it's ground floor or up.
- Type of build — a second-storey addition requires structural reinforcement of the lower level.
- Site conditions — slope, access, soil class and overlays.
- Whether the extension contains a wet area or new kitchen.
- Design fees, council approvals, BASIX/NatHERS energy compliance.
Home Extension in Perth.
Perth pricing has been moving upward with mining-driven labour competition; trades can be harder to secure for smaller residential jobs.
Frequently asked questions
How much does a home extension cost in Perth?
In Perth, a typical home extension costs between $99,750 and $336,000 in 2026, with most projects landing around $189,000. Pricing varies with size, finish level, complexity and your specific site.
How long does a home extension take?
Design and approvals typically take 4–8 months. Construction is 4–9 months depending on size and complexity. Most projects from idea to finish run 12–18 months.
Is a second-storey addition cheaper than building a new home?
Not necessarily. The per-m² rate is often higher than a ground-floor extension or a new build, because you're reinforcing the lower level and working with existing services.
What's NOT included in the estimate?
Major site works (rock excavation, retaining walls), demolition beyond the extension footprint, soft landscaping, and furniture/appliances. Design fees are budgeted but final architect / draftsperson fees vary.
See local pricing for your city
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