Granny flat finance
Yes, you can usually finance a granny flat, most often by borrowing against the equity in your home, or with a loan that pays the builder in stages. Two questions decide whether it works: whether the lender will count the rent the granny flat earns when it assesses the loan, and whether council will approve it on your block. It's also worth knowing that a granny flat rarely adds as much to your home's value as it costs to build.
Rent, or family?
For rent. A second income from the same block. The finance question is whether the lender will count that rent, and how much of it.
For family. Somewhere for a parent, an adult child or a carer to live. There's usually no rent, so the loan has to be paid from your income alone.
How to pay for it
Your home's equity. Increase your loan, or use money you've paid ahead, if there's enough equity and your income covers the bigger loan.
A construction-style loan, paid to the builder in stages. Lenders often require one when they're lending against the value once it's built: some lenders assess any renovation that relies on the finished value as a construction loan.
Cash or savings, if you have them, which avoids the lending question altogether.
Will a lender count the rent?
This is the question that decides whether a granny flat built for rent stacks up, and lenders don't all answer it the same way. Some will count expected rent from a granny flat, usually less than the full amount, to allow for vacancies and costs. Some count it only once it's rented with a lease in place. Some don't count it at all, or only where the granny flat is approved as a separate dwelling. The difference can decide how much you can borrow to build it.
Ask before you sign with a builder, not after.
If it's for family, not rent
With no rent coming in, the lender looks only at your income to cover the bigger loan. If the family member living there contributes, it usually doesn't count as income unless there's a formal arrangement the lender accepts. If they're helping pay for the build, how that's set up, as a gift, a loan or a share in the property, matters for both of you, and is worth getting advice on before any money changes hands.
What it adds to your home's value
A granny flat often adds less to a valuation than it cost to build. Valuers look at what buyers in your area would pay for a home with one, and that depends on the street, the block and the quality of the build. If you're counting on the added value to cover the loan, or to refinance later, have the numbers checked before you commit.
When you sell, a granny flat can widen your buyer pool, to families wanting room for a parent and investors wanting two rents, or narrow it, for buyers who just want a yard.
Council and planning: where these projects stall
Every state sets its own rules, and every council its own requirements for block size, setbacks and the size of the second dwelling. Check before you pay for plans.
In Queensland, since 26 September 2022, a secondary dwelling can be rented to anyone, not just to family. It has to be secondary to, and go with, a main home on the same block; it can't be built on its own. The state's planning department still says to speak to your council about whether you need development approval.
Can a granny flat be sold separately?
Usually not. A granny flat sits on the same title as the main home, and in Queensland a secondary dwelling can't exist without one. Selling it on its own would mean subdividing the land, which is a separate approval with its own requirements, and isn't possible on many blocks.
Build one, or buy a home that already has one
Build one. You choose the design and the timing, on a block you already own. You carry the council approval, the build risk and the cost of the build itself.
Buy one. The granny flat is already built and, ideally, already approved and rented, so you can see what it earns. You pay for it in the purchase price, and you need to check its approvals as carefully as the house.
Granny flat questions
Usually, yes: by borrowing against your home's equity, or with a construction-style loan that pays the builder in stages. Your income has to cover the bigger loan.
Thinking about a granny flat?
Tell me what your home is worth and what you owe, what the granny flat would cost, and whether it's for rent or for family. I'll tell you how you could fund it, whether a lender would count the rent, and what to check with council first.
You'll hear back within the hour in business hours, and by 9am the next business day after hours.
Sources
- 1
Queensland Government, Planning, "Secondary dwellings providing housing solutions" (updated 21 July 2026). Read 2 October 2026.
- 2
One lender's residential home loan credit guidelines (the lender isn't named). Read 27 August 2026.
Updated 2 October 2026