Granny Flats & Home Extensions in Perth metro
Granny flats and home extensions in Perth
This category covers builders who add living space to an existing block: detached granny flats (often called ancillary dwellings in WA), rear or second-storey extensions, and room additions that tie into the original house. The work runs from design and council or R-Codes checks through to slab, frame, services connections and final handover.
When comparing the 73 builders listed here, start with relevant experience. Ask to see finished jobs of the same type and size as yours. Check the builder holds a current WA building registration and home indemnity insurance where required, and that the quote spells out inclusions such as site works, power and water connections, and driveway or fencing changes. A fixed-price contract with a clear variations process matters more than a low headline figure.
Our scoring weighs review quality, consistency and how complete each business profile is, so you can shortlist without reading hundreds of comments. You can see how it works on the methodology page, or go straight to the ranked guide to granny flats and extensions for the top-scoring builders.
Connect with granny flats & home extensions
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All granny flats & home extensions, ranked by score and relevance
We found 73 businesses offering granny flats & home extensions; 22 met the criteria for the scored directory. The order weighs each business's overall score by how much of its reviewed work is granny flats & 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 an enquiry through our forms, we may share it with partner providers who can do the work, and we may earn a referral fee from those introductions. Our rankings and scores are based only on our published scoring method and are never influenced by referral fees.
Common questions about granny flats & home extensions
- How much does a granny flat cost in Perth?
- As a rough guide, a one or two bedroom granny flat often lands between $100,000 and $200,000 or more, depending on size, finishes, site access and service connections. Extensions are usually priced per square metre and vary widely. Always get fixed-price quotes in writing.
- Do I need council approval for a granny flat or extension?
- Usually yes. In WA you generally need a building permit, and a development approval may also apply depending on your local government and the R-Codes. Some small works are exempt, so confirm with your council before you commit.
- How long does the build take?
- Design and approvals commonly take a few months. Construction of a typical granny flat runs about 3 to 5 months, and extensions can take longer because they tie into the existing house.
- How can I judge a builder's quality?
- Visit a completed job if possible, check registration and insurance, read recent reviews for how problems were handled, and confirm the contract states inclusions, payment stages and timelines clearly.
Guides to choosing granny flats & home extensions
- Granny flat and home extension costs in Perth: what changes the price
Typical cost ranges for granny flats and home extensions in Perth, and the site and design factors that push the price up.
- Building a granny flat for an aging parent in Perth: what to consider
Practical and design considerations for building a granny flat so an aging parent can live nearby, from accessibility to council rules.