Floor Space Ratio and Height Limits in NSW: What They Cap on a Development Site

A zone says what kind of building is allowed on a site. Two other controls say how much. Floor space ratio caps the floor area, and a maximum height caps how tall the building can be. Together they set the yield on a block, and they are the first numbers a developer reads off the map.

This post covers how the Standard Instrument (the template every NSW local environmental plan is built from) defines and measures each one. How the zone itself is read is in our post on the R2 low density residential zone, and what a variation to either number takes is in the clause 4.6 post.

What does floor space ratio measure?

Clause 4.4 of the Standard Instrument says the maximum floor space ratio for a building is not to exceed the ratio shown for the land on the Floor Space Ratio Map. Clause 4.5 defines the term: the floor space ratio of buildings on a site is the ratio of the gross floor area of all buildings within the site to the site area.

That makes it a simple division. A site of 600 sqm with a ratio of 0.5 to 1 can carry 300 sqm of gross floor area. A site of 1,200 sqm with the same ratio can carry 600 sqm. The ratio does not say how the floor area is arranged, so two buildings of the same floor area can have different heights and footprints and still meet it.

The Standard Instrument notes that different ratios can be shown for different zones, for different land in the same zone, or for different uses within a building. A plan can also set the ratio partly from the map and partly by other means.

What counts as gross floor area?

The Dictionary defines gross floor area as the sum of the floor area of each floor of a building, measured from the internal face of external walls, at a height of 1.4 metres above the floor. It includes mezzanines and habitable rooms in a basement or attic.

It excludes several things:

• common vertical circulation such as lifts and stairs
• basement storage, vehicle access, loading areas, garbage and services
• plant rooms, lift towers and other areas used only for mechanical services
• car parking that meets any requirement of the consent authority, including access to it
• space used for loading or unloading goods
• terraces and balconies with outer walls less than 1.4 metres high
• voids above a floor

Two consequences matter for a feasibility. A compliant basement garage does not use up floor space ratio, but a basement room that is habitable does. And an enclosed balcony with walls over 1.4 metres high is floor area, so a design that relies on large covered terraces can be closer to the limit than the drawings suggest. Councils can add their own definitions around these, so the plan for your council is the one to read.

How is site area worked out?

The ratio is applied to the site area, and clause 4.5 has rules for that. Where development is on one lot, the site area is the area of that lot. Where it is on two or more lots, the area counts for lots that share at least one common boundary with another lot in the development.

Land is left out of the site area where the development is prohibited on it, and a lot cannot be added to the site area unless the development includes significant development on that lot. Clause 4.5 also lets a consent require a covenant so that floor area is not counted twice across lots that were consolidated for the purpose.

The same clause says the gross floor area of existing buildings inside the site boundaries counts towards the total, whether or not the proposal touches them. A site with a house you plan to keep has less floor space available than a cleared one. This is also why lot amalgamation can change what a group of lots can carry: a larger site area at the same ratio means a larger building, subject to the other controls.

How is building height measured?

Clause 4.3 says the height of a building is not to exceed the maximum height shown for the land on the Height of Buildings Map. The Dictionary measures it in metres as the vertical distance from ground level (existing) to the highest point of the building. It includes plant and lift overruns and excludes communication devices, antennae, satellite dishes, masts, flagpoles, chimneys, flues and the like. A plan can also set height as a reduced level, measured from the Australian Height Datum.

Ground level (existing) is defined as the existing level of a site at any point. The measurement is therefore taken from the natural surface beneath each part of the building, not from a single level at the front door. On a sloping block the height at the low side is greater than at the high side, which is why building on a sloping block is a design question as much as a construction one.

The Standard Instrument also notes that different heights can be shown for different zones or for different land in the same zone, and that a plan can modify the height limit in specific circumstances, such as protecting overshadowing of public open space or for air safety.

Where do these numbers come from for your block?

They sit on the maps that accompany your council's local environmental plan. The NSW Planning Portal spatial viewer shows the zone, floor space ratio, height and lot size layers by address. The section 10.7 planning certificate lists the planning controls that apply to the land, as covered in our post on section 10.7 certificates.

Two cautions apply. A state policy can set its own numbers where it applies, which is how the low and mid-rise housing standards work in the areas they cover, and those can differ from the local plan. And a development standard on a map is not always the last word, because clause 4.6 allows consent to be granted for a variation in some cases.

What to check before you price a site

• The zone, the floor space ratio and the height on the maps for your exact lot.
• The site area you can actually use, after any land the development cannot be carried out on.
• The gross floor area of any building you are keeping.
• Whether a state policy applies a different standard to the block.
• Whether the slope changes the height outcome at the low side.

We run these checks against a block before a feasibility is built on top of it, because a wrong ratio carries through every line of the numbers. Ask us for an assessment and the controls come back with the yield.

Common questions

What is floor space ratio in NSW?

Floor space ratio is the gross floor area of all buildings on a site divided by the site area. Clause 4.5 of the Standard Instrument local environmental plan defines it that way, and clause 4.4 says a building must not exceed the ratio shown for the land on the council's Floor Space Ratio Map. A ratio of 0.5 to 1 on a 600 sqm site allows 300 sqm of gross floor area.

Where do I find the floor space ratio and height limit for my block?

On the Floor Space Ratio Map and Height of Buildings Map that sit behind your council's local environmental plan. The NSW Planning Portal spatial viewer shows them by address. Not every plan applies both controls to every zone, so a blank on one map means that control is not set on the map for that land, and the planning certificate is the place to confirm what applies.

How is building height measured in a NSW local environmental plan?

The Standard Instrument measures it in metres as the vertical distance from existing ground level to the highest point of the building, including plant and lift overruns but excluding items such as antennae, flagpoles and chimneys. Because it starts from existing ground level at any point on the site, a sloping block can make a building taller on the downhill side than the number suggests.

Does a garage or basement count towards floor space ratio?

Car parking that meets the consent authority's requirements, and the access to it, is excluded from gross floor area, as are basement storage, vehicle access, loading and services areas. Habitable rooms in a basement or attic are included. Check your own local environmental plan, because councils can adjust the definitions that sit around the standard.