For most Perth blocks, yes. Analysis by Archistar and CoreLogic found a granny flat could lift a home’s value by up to 30 per cent and add around 27 per cent in weekly rent. With WA rules now letting compliant builds skip planning approval, the numbers deserve a proper look. This guide covers the value uplift, the rent, the rules and the cost.
Key Takeaways
- Archistar and CoreLogic analysis found a granny flat could add up to 30 per cent to home value and around 27 per cent to weekly rent (Property Council of Australia).
- Perth median unit rents are $620 per week for one-bedroom and $700 for two-bedroom units (REIWA, August 2026).
- Since April 2024, a compliant WA granny flat up to 70sqm needs no planning approval, and it can be rented out.
- Classic WA one-bedroom builds start from an estimated $80,000 to $110,000; the final figure always comes from a written quote.
How Much Value Does a Granny Flat Add?
Research by Archistar and CoreLogic found more than half a million homeowners in Sydney, Melbourne and Brisbane could lift their home’s value by up to 30 per cent by building a granny flat, with a two-bedroom unit adding about 27 per cent in extra weekly rent.
That study looked at the east coast, but the driver is identical in Perth: a second self-contained dwelling on one title means extra accommodation that buyers and valuers price in. How much you gain depends on your suburb, the block and the build quality. A well-built 60sqm one-bedroom won’t add the same as a 70sqm two-bedroom, but both add something a shed never will.
Analysis by Archistar and CoreLogic found building a granny flat could lift an Australian home’s value by up to 30 per cent and add around 27 per cent in weekly rental income, making an ancillary dwelling one of the highest-returning structures a homeowner can add to their block.
How Much Rent Could a Granny Flat Earn in Perth?
Perth’s rental market gives a granny flat real earning power. REIWA’s Perth Metro data (August 2026) puts median unit rents at $620 per week for a one-bedroom and $700 for a two-bedroom. A backyard granny flat typically rents below an equivalent standalone unit, so treat these medians as a reference point rather than a promise. Even at a discount, the annual income against a build in the $100,000s is hard to ignore.
| Closest comparable (Perth Metro) | Median weekly rent |
| 1-bedroom unit | $620 |
| 2-bedroom unit | $700 |
| 3-bedroom unit | $800 |
Source: Landgate/REIWA, updated August 2026. Actual granny flat rent depends on your suburb, finish and inclusions.
Can You Rent Out a Granny Flat in WA?
Yes. WA planning rules allow an ancillary dwelling to be rented out, and the State Government’s granny flat reforms explicitly promote them as rental supply. Since 10 April 2024, a compliant granny flat up to 70sqm needs no planning approval on a residential lot of any size. A building permit is still required; our guide to granny flat council approval in WA walks through exactly what applies.
The flexibility is the quiet win here. Many owners build for a parent first, then rent the flat out years later when circumstances change. Either way, the value sits on your title the whole time.
What Does It Cost Against the Value It Adds?
Classic WA’s Perth granny flat builds currently range from an estimated $80,000 for an entry one-bedroom through to $185,000 or more for a custom two-to-three-bedroom design. These are estimates only; your written quote is the final figure. Our granny flat cost guide for Perth breaks down what drives the price.
| Design type | Size guide | Estimated range |
| 1-bedroom entry | ~48sqm | $80,000 to $110,000 |
| 1-bedroom standard | ~60sqm | $100,000 to $130,000 |
| 2-bedroom | ~65 to 70sqm | $130,000 to $160,000 |
| Custom 2 to 3 bedroom | up to 70sqm | $150,000 to $185,000+ |
Set those figures against a potential value uplift and years of rental income, and the maths is why granny flats keep appearing in Perth backyards. Browse the Classic WA granny flat designs, all made in WA and built to stay within the 70sqm cap.
Frequently Asked Questions
Are granny flats a good investment in Perth?
The data leans yes. Archistar and CoreLogic analysis points to up to 30 per cent extra home value and around 27 per cent extra weekly rent, while Perth unit rents sit at $620 to $700 per week (REIWA). Returns still depend on your suburb, build cost and rent achieved.
Can I rent my WA granny flat to someone outside the family?
Yes. WA’s rules don’t limit ancillary dwellings to family members, and the State Government promotes granny flats as rental housing. Normal WA tenancy laws apply once you take on a tenant, and some councils have extra rules for short-stay use, so check before listing.
Does a granny flat help when you sell?
It widens your buyer pool. Multigenerational families, buyers wanting a home office or studio, and investors chasing rental income all pay attention to a compliant self-contained dwelling. A quality build with proper approvals reads as an asset, not an afterthought.
Run the Numbers on Your Block
If you’re weighing up whether a granny flat stacks up on your block, start with our complete WA owner’s guide, then talk to the Classic WA team about designs and a written quote. Finance options are available too. Our showrooms are at Joondalup (37 Winton Road) and Canning Vale (5 South Street).