Cost & Budget
What a realistic budget needs to cover.
A useful budget covers the complete project — not only the granny flat itself, but the design, approvals, services and site works required to build it.
“How much does a granny flat cost?” is usually the first question — and it’s one worth answering properly. A realistic budget needs to cover the whole project, not just the home itself.
Typical completed projects from AMGCUBE start from $250,000, including design, engineering, approvals, construction and handover. That starting point already reflects a full picture — which is why the final number for your block can still sit above or below it.
Why similar granny flats cost differently
Two homes of the same size and layout can come in at quite different prices, because the floor plan is only part of the figure. The rest is decided by your property:
- The site. Access, slope, soil, retaining work and how far services have to run all affect foundations, drainage and construction effort.
- Approvals. Design, engineering, certification and any council or authority requirements vary from one area to the next.
- External works. Driveways, landscaping and other works outside the building footprint are often the least predictable part of a budget.
- Finishes and inclusions. The level of finish inside the home moves the number up or down more than most people expect.
The home is only part of the budget
A 2 bedroom granny flat typically sits in the 60–100 m² range. But the completed project also includes:
- Design, engineering and consultant fees
- Required approvals and certification
- Site preparation, foundations and drainage
- Connections for sewer, water and power
- Construction, fixtures, fittings and handover
This is why we look at the property before confirming a budget. Once the site and scope are understood, we prepare a fixed-price proposal — not a moving estimate that creeps up as the project goes along.
What to watch for in a granny flat quote
When comparing quotes, look beyond the headline figure:
- Does it include approvals and certification, or are they quoted separately?
- Is site work and service connection included?
- Is the proposal fixed-price once the scope is agreed?
- What happens if a site condition shows up after construction starts?
Send us your property address and we'll assess the site and confirm what a completed project would involve before you commit to anything.