Tasmanian backyards are set for a major change, as the state government works on increasing granny flat sizes by 50% amid growing calls to make it easier to build these increasingly popular dwellings nationwide.
Granny flats are gaining traction as one way to boost the supply of new homes and help ease the housing affordability squeeze in Australia.
It comes as home builders expect to construct 10-times more granny flats across the country in 2026 than they did in 2022, according to a recent survey by the Housing Industry Association (HIA).
In Tasmania, the state government is progressing plans to increase granny flat sizes from 60 square metres (sqm) to 90 sqm soon, although a start date hasn't been confirmed.
A 90 sqm granny flat is roughly the equivalent of an older, more spacious two-bedroom apartment, and the 50% upweight in size will offer more practicality and flexibility.
Tasmanian housing and planning minister Kerry Vincent said current granny flat sizes were ideal for singles or couples but locked out families.
"These changes give families room to grow as life changes, while maintaining the ability to upsize their existing property,” Mr Vincent said.
The Tasmanian state government is working on increasing granny flat sizes to up to 90 sqm. Picture: Brad Fleet.
“There is an appetite in the market for this type of medium-density build, and supersized granny flats really do meet that requirement.
“It allows us to build greater density in our urban areas meaning intergenerational homes, greater home security and support for the construction industry.”
Housing affordability is a major issue in the state, with a median-income household only able to afford just 8% of homes sold over the past year, according to the 2025 PropTrack Housing Affordability report.
Hobart's median house price jumped 9.5% to $778,000 during the year to March. Picture: Getty
Buyers face rising home prices there too, with the median house price in Hobart jumping 9.5% to $778,000 in the 12 months to March, and unit prices increasing 6.8% to $599,000, according to PropTrack.
Throughout the rest of Tasmania, the median house price rose 11.5% to $593,000 during the same period, as unit prices soared 11.8% to $488,000.
REA Group senior economist Anne Flaherty said the granny flats move was positive because it gives people more choice about what they built on their land.
"A massive expense when it comes to adding to the supply of homes is the purchase of land, so people who already own land will be able to add a larger dwelling to their property for a family member to live in or to rent out," Ms Flaherty said.
"I think it's going to give people more flexibility. The pre-existing size was a bit limited, so this change should be helpful."
As prices rise, experts say the main way to improve housing affordability in the state and around the country is to increase the supply of new homes.
HIA Tasmania executive director Benjamin Price said granny flats were one of the quickest and most sensible ways to boost housing supply, particularly in established suburbs close to jobs, schools and services.
“Bigger granny flats mean bigger choice, and lifting the size limit helps get unnecessary regulation out of the way of sensible housing options,” Mr Price said.
“If we’re serious about housing supply, then freeing up infill opportunities is simply common sense.
“At 90 sqm, this puts Tasmania at the very top end nationally for granny flat size, giving families and builders flexibility you simply don’t see in most other states.”
Granny flat regulations vary across the country, prompting the HIA to call on the federal government to create a unified national framework for granny flats and secondary dwellings.
For example, planning permits aren’t required for second dwellings up to 60 sqm in Victoria and South Australia, and up to 70 sqm in Western Australia.
The HIA pointed to recent reforms in New Zealand, where homeowners can secure planning exemptions to build granny flats up to 70 sqm nationwide by following standardised design rules.
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