One of the most common things Melbourne homeowners hear when they start looking into building a granny flat is this: “Your block is too small.” Sometimes that is true. But a significant number of the time, it is not — and the person saying it is working from outdated information.
Victoria’s planning rules around minimum block size granny flat requirements changed significantly in late 2023. If you were told you could not build before those reforms, it is worth checking again. You may be eligible now when you were not before.
What Was the Old Minimum Block Size Rule?
Prior to Victoria’s December 2023 planning reforms, most councils required a minimum lot size of 300sqm before a secondary dwelling could be approved. Some councils set even higher thresholds through local planning policies.
This meant homeowners on smaller inner-city or middle-ring blocks — properties that are perfectly capable of accommodating a compact secondary dwelling — were simply locked out of the process regardless of what they wanted to build or how well-designed the proposal was.
That threshold has now been removed for the most common type of secondary dwelling build.
What Are the Current Rules in Victoria?
Under Victoria’s current planning framework, there is no minimum lot size for secondary dwellings under 60sqm in a standard residential zone. This is the single most important change from the 2023 reforms for Melbourne homeowners with smaller blocks.
What this means in practice: if your block is 250sqm, you can potentially build a 60sqm secondary dwelling on it — subject to setback requirements, site coverage limits and the building permit process. If your block is 400sqm, you have more flexibility around siting and floor plan choice, but the minimum lot size is no longer the barrier it once was for either size.
The secondary dwelling still needs to comply with setback requirements, site coverage limits and energy efficiency standards. But the minimum lot size itself is no longer a fixed threshold that excludes smaller properties outright.
For the most current planning guidance, the Victorian Planning Authority publishes up-to-date information on secondary dwelling requirements across Victoria.
Are There Any Situations Where a Minimum Size Still Applies?
Yes. The removal of the minimum lot size applies to secondary dwellings under 60sqm in standard residential zones. There are situations where different rules apply.
Planning overlays. If your property sits within a heritage overlay, flood zone, bushfire management overlay or environmental significance overlay, a planning permit is required regardless of the size of the secondary dwelling.
Secondary dwellings over 60sqm. If you want to build a secondary dwelling larger than 60sqm, the planning permit pathway applies and councils may have more discretion over minimum lot size requirements.
Rural and low-density zones. Properties in Rural Living Zone, Green Wedge Zone or Low Density Residential Zone carry entirely different secondary dwelling provisions and the standard urban rules do not apply.
What Else Determines Whether Your Block Can Accommodate a Secondary Dwelling?
Minimum lot size is just one part of the equation. The other factors that determine whether your block can accommodate a G-Flat™ are:
Site coverage. Your local planning scheme sets limits on how much of the lot can be covered by buildings. On a smaller block, site coverage can be the limiting factor even when lot size is no longer an issue.
Setback requirements. Every secondary dwelling needs to meet minimum setback distances from the front, rear and side boundaries. On a narrow or compact block, these setbacks can significantly reduce the area available for the secondary dwelling footprint.
Private open space. A secondary dwelling cannot be positioned in a way that removes all functional outdoor space from the primary residence.
Which G-Flat™ Floor Plans Work Best on Smaller Blocks?
Innovista’s G-Flat™ range includes floor plans specifically suited to blocks where space is at a premium.
The Aurora G-Flat™ is a long, narrow layout measuring 13.2 metres by 4.5 metres. It runs along the boundary and is particularly effective on narrow or side-access blocks where a wider footprint is not available.
The Stella G-Flat™ uses an L-shape layout measuring 11.4 metres by 4.2 metres with a 2.9 metre return. It works well on corner blocks and properties where the available building envelope is irregular.
The Lana G-Flat™ at 9.9 metres by 6.1 metres is a balanced rectangular layout that fits comfortably into most standard suburban backyards.
The Sirius G-Flat™ at 8.5 metres by 7 metres uses a compact square footprint — ideal for blocks with a wider but shallower yard dimension.
All five floor plans sit at 60sqm, which keeps them within the no-planning-permit threshold for most residential zones in Victoria.
The Next Step Is a Site Assessment
The only way to know for certain what your specific block can accommodate is to have it assessed properly. Online calculators and general guides can give you a starting point, but they cannot account for your zone, your overlays, your existing site coverage or your specific block dimensions.
Innovista offers a free site assessment where our team visits your property, checks all of the relevant planning parameters and gives you a clear, honest answer about what is possible — and which G-Flat™ floor plan is the right fit.