Site coverage: what it means and how much you can build

Site coverage, or site cover, is the share of a lot covered by roofed buildings and structures, written as a percentage of the lot’s area. The house, the garage, a carport, a roofed patio and a shed count, while open decks, driveways and paving usually do not, and your zone sets the most you can cover. Everything already under roof counts towards that limit, which is why site coverage so often decides the size of a backyard project.

To check a particular block, type its address into RapidSiteplan: it reads the lot and the rules that apply there and checks the structure you place against them, in minutes.

How is site coverage worked out?

Add up the roofed footprint already on the block, add what you are proposing, divide by the lot area. That figure is what the assessor checks against your zone's limit. A site plan is expected to state it both before and after the build.

What counts towards site coverage?

Usually counts: the house, garage, carport, patio, shed, and most roofed outdoor areas
Usually does not: open decks, driveways, paving, pools and paths
Depends on the scheme: covered but open-sided structures, eaves beyond a stated overhang, and unroofed pergolas

The definitions differ between schemes, which is why the number is worth checking rather than assuming. Western Australia works the other way round, with a share of the lot that has to stay open space.

Where does your limit come from?

From the rules for the zone your lot sits in, and in some states from the state's own siting rules. Some schemes set a different limit for small lots, and some vary it by lot size in bands, so two neighbouring blocks can carry different limits.

Why does it decide small projects?

An established block with a house, a garage and an existing patio can already be close to its cap. The new carport is then not refused on its own merits, it is refused on arithmetic nobody did at quote time. Working the coverage out first tells you the size that actually fits, which is a far better conversation than redesigning after a knockback. Going over the limit is usually a planning decision for council rather than a building approval matter.

What only your address can answer

the zone your lot is in, and the limit that goes with it
whether a small-lot or lot-size rule changes the limit
the lot's area, and how much of it is already under roof
how your scheme treats eaves, open-sided structures and pergolas

RapidSiteplan reads your own block from its address: the boundaries, the buildings already on it, the rules that apply there and any overlay or easement, and checks what you plan to build against them on a scaled site plan.

Search your address to start. Site plans and assessments in minutes.

Sources: the siting rules a site plan is read against, by state, all read in September 2026: Queensland Housing Code (Qld); State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 (NSW); Building Regulations 2018 (Vic); Planning and Design Code (SA); Residential Design Codes Volume 1 (WA); Tasmanian Planning Scheme, State Planning Provisions (Tas); Planning (Exempt Development) Regulation 2023 (ACT); NT Planning Scheme 2020 (NT).

Common questions

What does site coverage mean? The proportion of your lot covered by roofed structures, written as a percentage of the lot area. The rules for your zone cap it so blocks keep open space for drainage, light and setbacks.

What counts towards site coverage? Roofed structures generally count: the house, the garage, a patio, a carport, a shed. Open decks, driveways and paving usually do not, though schemes differ on covered outdoor areas, so check the definition your council uses.

What is my site coverage limit? It is set by the rules for your zone, and some schemes apply a different limit to small lots. Your site plan needs to state coverage before and after the build so the assessor can check it against the limit that applies.