With rents climbing year after year, many young Australians are trapped paying off someone else’s mortgage instead of building their own future. But there’s a smarter way: instead of sending $600—or more—every week to a landlord, your kids could be contributing to an asset that grows your family’s wealth.
Building a granny flat in your backyard lets you do exactly that. Your children get affordable, stable housing, while you increase the value of your property and even generate extra income. It’s a win-win that helps everyone save money and plan for the future. With 2025 Interest rates dropping, now is a good time to look at this opportunity.
For many families, this simple step turns a costly rental situation into a wealth-building opportunity — and it’s easier to make the numbers work than you might think.
The Example Build
- Granny flat build cost: $250,000
- Deposit: $50,000 (20%)
- Borrowed amount: $200,000 via equity from your home
- Interest rate: 3.99% p.a. (variable, interest-only for illustration)
Loan Repayments at 3.99%
- $200,000 × 0.0399 = $7,980/year in interest
- Monthly interest = $7,980 ÷ 12 ≈ $665/month
What Your Kids Pay Instead of Rent
If your son or daughter pays $600/week for the granny flat:
- $300/week × 52 weeks = $15,600/year
- That’s $1,300/month
Your Cashflow
- Loan cost: $665/month
- Child’s contribution: $1,300/month
- Surplus: ~$635/month (before tax)
This surplus can cover insurance, maintenance, or offset your own mortgage, while still providing an affordable living option for your child.
What They Save
By moving from $600/week rent to $300/week contribution:
- They save $300/week, which totals $15,600/year
- Over 5 years, that’s $78,000 saved, not including bond deposits, moving costs, or other rental expenses
Plus, that’s money helping build equity in your property and family assets, not someone else’s.
The Tax Advantage for You
If you later decide to rent the granny flat to someone else, you can claim depreciation:
- Capital works deduction: $250,000 × 2.5% = $6,250/year
- Plant & equipment deduction: $2,000–$4,000/year in early years
That’s up to $10,000/year in deductions, reducing your taxable income. Check with a licensed quantity surveyor for a full depreciation schedule and ensure compliance with the ATO.
Note: While a granny flat rented to family is still considered an income-earning asset, you should consider the capital gains tax implications if you later sell the family home. Professional advice is recommended.
Future Flexibility
Once your kids move out, you have options:
- Rent it out at market rates ($400–$550/week in many areas)
- Use it for extended family or guests
- Sell your home with the granny flat as a value-adding feature
The Bottom Line
A granny flat isn’t just a building — it’s a financial tool that:
- Gives your kids a stable, affordable place to live
- Lets you recoup costs and even profit while helping them
- Becomes a long-term asset for your family’s future
With smart planning, your granny flat can turn rising rents from a drain on your family into a wealth-building opportunity — keeping your kids housed and contributing to a brighter financial future.
This is not specific financial advice and is provided for illustration purposes only. You should always consult your tax and financial advisors before making a big decision