Home Extensions in Perth metro
A guide to choosing a home extension builder in Perth, what the work involves, what drives cost, and how our ranking of 88 local contractors can help.
A home extension adds new floor area to an existing house: a second storey, a rear or side addition, a new bedroom wing, or a bigger kitchen and living zone pushed out into the backyard. It's a bigger job than a renovation because it usually touches footings, framing, roofing, and services (plumbing, electrical, sometimes stormwater) rather than just refreshing what's already there. In Perth, extensions also have to work with the existing house's orientation, slab type, and often heritage or R-Codes setback rules depending on the suburb, so local knowledge of council requirements matters as much as trade skill.
When you're comparing builders, look past the glossy photos and check a few practical things: are they registered builders (not just tradespeople) with current insurance and a real defects liability period, do they handle the whole job including permits and engineering, and will they give you a fixed-price contract rather than a loose estimate that grows once walls are opened up. Ask to see a finished extension in person if you can, not just renders. Timeframes and disruption to your household are worth discussing upfront too, since you'll likely be living on site during at least part of the build.
We've scored all 88 home extension businesses operating across Perth metro on consistency of past work, responsiveness, and verified customer feedback. For a ranked shortlist, see our best renovation contractors guide, and for how we calculate scores, read our methodology.
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All home extensions, ranked by score and relevance
We found 88 businesses offering home extensions; 67 met the criteria for the scored directory. The order weighs each business's overall score by how much of its reviewed work is home extensions, so a lower-scored specialist can rank above a higher-scored generalist. Filter and sort below, or open the full map view.
When you submit a form on this site, your enquiry may be shared with partner providers able to do the work. We may receive a referral fee, but our rankings and scores are based on our published method only and are not affected by these fees.
Common questions about home extensions
- How much does a home extension cost in Perth?
- It varies a lot by scope, but a single-storey extension (extra bedroom, bathroom, or living space) typically runs from the low tens of thousands for a basic build up to well over $100,000 for a larger addition with a new kitchen or ensuite. A second-storey addition costs more again because of structural upgrades to the existing footings and walls. Get at least three fixed-price quotes rather than relying on a single ballpark figure, since site conditions (slab type, access, soil) change the price quickly.
- How long does a typical extension take?
- A straightforward single-storey extension often takes three to six months from slab to handover, not counting design and approval time, which can add several more months depending on whether council or private certification is used. Second-storey additions and complex sites usually take longer.
- What should I expect during the build?
- Expect some disruption: dust, noise, tradespeople on site regularly, and possibly a period without full use of your kitchen or bathroom if the extension connects to them. A good builder will give you a rough schedule of trade stages (footings, frame, roof, lock-up, fit-out) so you know what's happening and when.
- How do I judge the quality of a builder before hiring them?
- Check their builder registration status, ask for addresses of past extensions you can view from the street or visit, and read customer feedback for patterns around communication and finishing quality rather than just star ratings. A builder who answers questions about council approvals and structural details clearly, without vague reassurance, is usually a safer bet.
Guides to choosing home extensions
- Home extension costs in Perth: what pushes the price up
What a Perth home extension typically costs by type and size, and the site factors that push a quote toward the top of the range.