Site coverage. The second number that limits your footprint.
FSR caps the floors. Site coverage caps the footprint. The two together decide whether you can build a courtyard, a two-storey, or just a sprawling single-level. Here is how to use both.
Floor Space Ratio limits how much total floor area you can build across all storeys. Site coverage limits how much of the lot the building footprint can cover. Both apply. Buyers and builders who think about FSR alone routinely discover, mid-design, that site coverage is the binding constraint.
This post explains site coverage, where it comes from, and how it interacts with FSR to shape the buildable envelope.
What site coverage is
Site coverage is the proportion of the lot covered by the building footprint, measured at ground level. It is expressed as a percentage.
A site coverage of 50% on a 600 square metre lot means the building footprint cannot exceed 300 square metres.
The footprint is the outline of the dwelling as projected onto the ground. Upper floors do not count separately. A two-storey dwelling with a 200 square metre ground floor and a 150 square metre upper floor has a site coverage of 200 square metres (the ground footprint), not 350.
Garages, attached carports, and major outdoor structures typically count. Eaves, awnings, and minor overhangs usually do not.
Typical site coverage by zone
In 2026, typical site coverage limits across Australian residential zones:
- R1 General Residential: 50-60%
- R2 Low Density Residential: 45-55%
- R3 Medium Density: 60-70%
- R4 High Density: 70-80%
- Character/heritage areas: often 40-50% (stricter to preserve garden setting)
- Rural Residential: 10-20% (very low coverage to preserve open character)
Brisbane City Plan 2014 uses "building footprint" rather than "site coverage" for the same concept, with different category names.
How FSR and site coverage interact
The two work in combination to produce the buildable envelope.
Worked example: 600 square metre lot, R2 zone, FSR 0.5:1, site coverage 50%.
- FSR limit: 300 square metres total floor area
- Site coverage limit: 300 square metres footprint
Option A: single-storey 300 square metre dwelling. Hits both limits simultaneously.
Option B: two-storey 200 square metres ground + 100 square metres upper. Site coverage = 200 (33%). FSR = 300 (0.5:1). FSR is the binding constraint, site coverage has 17% headroom.
Option C: two-storey 150 + 150. Site coverage = 150 (25%). FSR = 300 (0.5:1). FSR is binding, site coverage has substantial headroom.
The shape of your build (sprawling single-level vs compact two-storey) determines which constraint binds.
When site coverage binds
Two scenarios where site coverage is the binding limit:
1. Single-storey on a tight lot
If you want a single-storey build for accessibility or family reasons, the ground floor is the entire floor area. Site coverage typically binds before FSR. On the worked example above, the maximum single-storey dwelling is 300 square metres (site coverage), but if FSR were 0.6:1 you could build 360 square metres of two-storey but still only 300 single-storey.
2. Wide, shallow lots
A 30m × 20m lot (600 sq m, 1.5:1 width:depth ratio) is easier to fully cover with a single-storey dwelling than a 60m × 10m lot of the same area. Wide lots tend to hit site coverage limits first. Long narrow lots tend to hit FSR limits first.
3. Mandatory rear yard or principal private open space
Many councils require a minimum rear yard or principal private open space (POS) — typically 16-25% of the lot area, with minimum dimensions like 3m × 4m. The POS requirement effectively reduces the maximum site coverage even further.
On a 600 square metre lot with a 20% POS requirement, 120 square metres is reserved for outdoor space. The maximum site coverage is therefore 480 square metres minus setbacks, not 600 minus setbacks.
When site coverage does NOT bind
Two scenarios where FSR is the binding limit:
1. Two-storey on a roomy lot
If you build vertically, FSR consumes faster than site coverage. A 600 square metre lot with FSR 0.5:1 can fit a 300 square metre two-storey dwelling on a 150 square metre footprint (25% coverage). FSR is binding, site coverage has 25% headroom.
2. High-density zones
In R3 or R4 zones with FSR of 0.9:1 or 2.0:1, you would need to cover almost the entire lot to hit FSR with a single-storey design. Most R3/R4 builds are multi-storey because the FSR allows it and site coverage is comparatively generous.
Why character areas use low site coverage
Heritage character areas often impose site coverage of 40% or less. The reason: preserving the "garden setting" of the streetscape. Suburbs like Mosman, Hunters Hill, Toorak, New Farm rely on the open-front-yard, set-back-dwelling, mature-garden aesthetic, and low site coverage is the rule that enforces it.
For a buyer in a character area: site coverage is almost always the binding limit, not FSR. The implication for design: your dwelling will be a tall compact mass rather than a sprawling low one.
The 30-second site coverage check
Before any bid:
- Look up the LEP/Planning Scheme for the lot's zone.
- Find the site coverage limit (usually in the DCP or the planning scheme code).
- Multiply by the lot area to get the maximum footprint.
- Sketch your preferred dwelling's footprint and compare.
If your preferred footprint fits, site coverage is not a constraint. If not, either compress to two-storey or accept a smaller ground-floor dwelling.
FSR and site coverage are two constraints, not one. The buyer who reads both knows what their lot can become. The buyer who reads only FSR discovers the second number from the architect's redesign quote.
