An important control in the NSW planning system is floor space ratio (FSR). It has become increasingly important in recent years, as all Councils across NSW have gradually adopted the state-wide standard LEP.
Lets look at the definition of floor space ratio that can be found in the standard LEP that applies to most areas of the state:
"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."
Once we've obtained the definition of floor space ratio, we need to consider the definitions of "gross floor area" and "site area" which are referenced above.
"Site area In determining the site area of proposed development for the purpose of applying a floor space ratio, the site area is taken to be:
(a) if the proposed development is to be carried out on only one lot, the area of that lot, or
(b) if the proposed development is to be carried out on 2 or more lots, the area of any lot on which the development is proposed to be carried out that has at least one common boundary with another lot on which the development is being carried out.
In addition, subclauses (4)–(7) apply to the calculation of site area for the purposes of applying a floor space ratio to proposed development.
"Exclusions from site area The following land must be excluded from the site area:
(a) land on which the proposed development is prohibited, whether under this Plan or any other law,
(b) community land or a public place (except as provided by subclause (7))".
"gross floor area means the sum of the floor area of each floor of a building measured from the internal face of external walls, or from the internal face of walls separating the building from any other building, measured at a height of 1.4 metres above the floor, and includes:
(a) the area of a mezzanine, and
(b) habitable rooms in a basement or an attic, and
(c) any shop, auditorium, cinema, and the like, in a basement or attic,
but excludes:
(d) any area for common vertical circulation, such as lifts and stairs, and
(e) any basement:(i) storage, and(ii) vehicular access, loading areas, garbage and services, and
(f) plant rooms, lift towers and other areas used exclusively for mechanical services or ducting, and
(g) car parking to meet any requirements of the consent authority (including access to that car parking), and
(h) any space used for the loading or unloading of goods (including access to it), and
(i) terraces and balconies with outer walls less than 1.4 metres high, and
(j) voids above a floor at the level of a storey or storey above".
In simple terms, if you have a gross floor area of 500 square metres on a 1000 square metre site, that makes a floor space ratio of 0.5:1.
While there has been an attempt to standardise the above definitions across the state in recent years, it is very important to read the LEP or SEPP applicable to your area carefully, as there can be variations. For example, State Environmental Planning Policy (Housing for Seniors and People with a Disability) 2004 contains a completely different definition of gross floor area that can be more generous to the standard definition above.
In general, the higher the maximum floor space ratio in an LEP, the more intense development that is permitted on a site. Other controls are important to consider, however, as often they can be limiting factors. For example a height limit of two storeys is going to limit the amount of floor area that you can practically accommodate on a site, regardless of the maximum floor space ratio.