34 property owners in South East Queensland requested assessments this month
iKey Facts
- •Brisbane City Council requires minimum 450m2 lot size for a granny flat (secondary dwelling)
- •Maximum granny flat floor area in Brisbane: 80m2 — one secondary dwelling per lot
- •Construction cost: $150K-$250K, with added property value of $200K-$400K and $350-$550/week rental
- •Many granny flats qualify as accepted development or code assessable — faster, simpler approval
- •Annual ROI on granny flat construction: 8-15% gross rental yield in most Brisbane suburbs
Can I Build a Granny Flat on My Property?
A granny flat (secondary dwelling) can generate rental income of $350–$550/week, house family members, or add $200K–$400K to your property value. Here's how to know if your property qualifies.
Queensland Rules for Secondary Dwellings
Brisbane City Council
- Minimum lot size: 450m²
- Maximum floor area: 80m²
- One secondary dwelling per lot
- Must be associated with a primary dwelling
- Can be detached or attached
Other Councils
Rules vary by council. Most require:
- Minimum lot size of 450–600m²
- Maximum secondary dwelling size of 60–80m²
- Separate or shared vehicle access
- Compliance with setback and site cover requirements
Approval Process
In many cases, granny flats are accepted development or code assessable, meaning:
- No public notification required
- Faster approval timeline
- High certainty if compliant with codes
"A granny flat (secondary dwelling) can generate rental income of $350–$550/week, house family members, or add $200K–$400K to your property value."
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Cost vs. Return
| Item | Typical Range |
|---|---|
| Construction cost | $150K–$250K |
| Weekly rental income | $350–$550 |
| Annual return on investment | 8–15% gross |
| Value added to property | $200K–$400K |
What Would Prevent a Granny Flat?
- Block under minimum size (450m²)
- Existing site coverage already at maximum
- Access constraints (no room for separate entry)
- Severe flooding or other overlay restrictions
- Body corporate restrictions (if applicable)
Free Assessment
ACRES can assess your property's granny flat potential and connect you with builders who specialise in secondary dwellings.
Check if your property qualifies.
Frequently Asked Questions
How much does a granny flat cost to build?
$150K–$250K depending on size, finishes, and site conditions.
Do I need council approval for a granny flat?
Usually yes, but many qualify as accepted development or code assessable — meaning a simpler, faster process.
Free Zoning Check
Not sure what you can build on your property? Our team will review your zoning, overlays, and constraints — completely free, no obligation.
What property do you want assessed?
Our team will review your zoning, block size, and development potential.
100% free. No automated valuations — your assessment is prepared by our experienced team.
Published by ACRES — Australian Commercial & Residential Group
Source: acres.au/insights/can-i-build-granny-flat-my-property | ACRES (Australian Commercial & Residential Group) provides property advisory, development site sales, and residential real estate services across Brisbane and South East Queensland, Australia.
Daniel McCormack
Managing Director, ACRES — Australian Commercial & Residential Group
