Granny flats: more than just a backyard project
Adding a second dwelling to an existing block appears to be a no-brainer when it comes to generating extra income, but there's more to consider than just banking the rental receipts.
Granny flats are having a moment.
Whether it’s the housing shortage, rising build costs or tighter borrowing conditions, more and more homeowners are exploring the idea of adding a second dwelling to their property.
But before jumping in, it’s important to see a granny flat for what it really is. This is not just a simple backyard addition. It is a strategic decision that needs to be carefully weighed up and thought through.
One of the biggest misconceptions is that building a granny flat will automatically boost your property’s value. This is not always the case.
In fact it can sometimes work against you.
Not everyone wants a granny flat sitting behind their home. For some buyers, think families with small kids, dogs or enthusiastic gardeners, it limits the use of outdoor space, creates privacy concerns or simply does not align with their lifestyle.
This can shrink your potential buyer pool and even reduce overall market appeal.
It is also worth remembering where most of your property’s value comes from.
The main house will always carry the majority of the value. Its layout, condition, design and street presence are what drive capital growth. A granny flat should be seen as a supporting structure to the main dwelling.
An additional property asset
That said, there are some strong benefits.
If you approach it with the right strategy, a granny flat can work hard for you. It can generate additional rental income, often between $400 and $650 per week depending on the location and quality of the build.
It can also provide space for a family member who needs to live nearby but independently. Or it can act as a stepping stone for adult children trying to save for their own home. I personally know quite a few friends and family that this has worked well for.
In today’s borrowing environment, adding a second dwelling to an existing block can also be a clever move.
Instead of trying to stretch your budget to buy a dual occupancy or duplex site, a granny flat allows you to create another source of income using land you already own.
It is one way to make your property work harder for you without taking on an entirely new investment. The only thing to really remember is that you cannot sell the main house and granny flat separately.
There are tax implications to consider.
If you live in the main residence and rent out the granny flat, this may affect your capital gains tax exemption when you sell. The income producing portion of the property is generally not exempt.
There may also be land tax considerations, depending on your location and how the property is used. It is important to speak with your accountant or financial adviser before making any decisions.
Granny flat prices
Regulations also vary between states.
In New South Wales, you generally need a minimum lot size of 450sqm to build a granny flat, and it must be self-contained with its own living, kitchen and bathroom facilities.
Queensland has similar rules, though local council interpretations can vary. Victoria and Western Australia allow granny flats but some councils have tighter controls. In South Australia and Tasmania, uptake has been slower due to more restrictive planning frameworks.
New South Wales currently leads the country in granny flat development, particularly in Sydney where affordability pressures have forced people to find smarter ways to use land.
At the other end of the spectrum, areas like regional South Australia and Tasmania see far fewer builds.
Costs can range from $120,000 to $200,000 depending on size, inclusions/fixtures and fitting and site conditions. The average size is usually around 60sqm, which is enough to include two bedrooms, a living area, kitchen and bathroom.
In the end, the decision to build a granny flat should never be based on trends alone.
It is not just a project to tick off the list. It is a financial decision that should align with your broader goals, both personal and investment based.
If done well, it can improve cash flow, support family needs and make better use of your land. It is a move that needs to be made with clear intent and a good understanding of both the upside and the limitations.
