🏡 Converting a Double Garage into a Granny Flat: A Smart Way to Add Value and Space
- Chris Morris
- May 17
- 2 min read

Are you looking to add extra living space to your property without the cost of building from scratch? Converting a double garage into a self-contained granny flat is a popular and practical solution. Whether it’s for elderly parents, teenage children, a rental opportunity, or even a private home office or studio—this cost-effective transformation can unlock incredible potential right in your backyard.
✅ Why Convert a Double Garage into a Granny Flat?
A double garage offers a solid structure, typically around 35–45m², which is an ideal base size for a compact, functional dwelling. By repurposing the space, you can:
Maximize your property’s footprint
Increase rental income potential
Accommodate multigenerational living
Create a private space for guests or remote work
Add resale value to your property

🧱 What’s Involved in the Conversion?
Converting a garage into a livable granny flat involves more than a simple makeover. Here's what typically needs to be done:
1. Design & Approval
You’ll need a well-thought-out floor plan that complies with your local council’s regulations. Most councils treat garage conversions as change of use, so you’ll likely need:
Planning approval
Building approval
Engineering and energy compliance reports
2. Insulation & Waterproofing
Garages aren’t usually built for year-round comfort. Walls, floors, and ceilings will need proper insulation and possibly waterproofing, especially if converting to a bathroom or kitchen.
3. Plumbing & Electrical
You’ll need professional trades to run plumbing for kitchens and bathrooms, as well as new electrical circuits for lighting, heating/cooling, and appliances.
4. Windows & Doors
Standard garages often lack sufficient natural light and ventilation. You’ll likely need to replace the garage door with a large window or sliding doors and add windows where needed.
5. Interior Fit-Out
Fit out the interior with:
Bathroom and kitchenette
Bedroom/living zone
Flooring, lighting, and paint
Storage solutions
🏗️ Sample Layout Ideas
Studio Design: Open-plan with bed, kitchenette, lounge, and compact bathroom
1 Bedroom Layout: Separate bedroom, open living/kitchen space, and full-size bathroom
Office + Guest Suite: Private office with a pull-out bed and bathroom
💰 What Does It Cost?
Garage conversions are typically more affordable than building a new granny flat from the ground up. Depending on location, finishes, and design, you can expect costs to start from $12,000–$100,000+, which is often far less than a new build.
⚖️ Things to Consider
Zoning and Council Regulations
Access and Privacy for the flat
Parking Requirements (especially if removing a garage from a property)
Stormwater and drainage needs
Bushfire/Flood/Heritage overlays (if applicable)
📐 Need Help Getting Started?
We offer affordable concept plans and custom design services for converting garages into granny flats—tailored to your block, budget, and needs. Our designs are ready to submit for approval or can be adapted to suit.
👉 Contact us today to discuss your garage conversion and see how easy it can be to turn underused space into smart living.
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