Setbacks, floor area and height decide where a new single storey home can sit and how big it can be. Under a complying development certificate (CDC) these limits are fixed numbers in the Housing Code. Here is how they work and where people get caught out.
Height: rarely a problem, but not never
The Housing Code caps a dwelling house at 8.5 m, measured from the natural ground level, meaning the ground before any excavation or fill. A typical single storey home is far below that. The limit can matter on a steep block, where the floor sits high above the lower side of the site, or where a design has a tall pitched roof.
If you go through a development application (DA) instead, council applies the height limit in its local environmental plan and any controls in its development control plan.
Setbacks to the front, sides and back
Front setback. The distance to the primary road depends on lot size. NSW planning guidance shows it ranging from 3 m on the smallest lots up to 10 m on lots of 1,500 m² or more. Where there are houses nearby, the setback can instead be based on the average of those neighbours.
Side setbacks. The NSW Planning Portal explains that the side setback is 0.9 m for building height up to 4.5 m, then grows as the building gets taller. Its example is a 15 m wide lot, where a building 7 m high needs 1.53 m. Most single storey walls stay below 4.5 m, so 0.9 m is often the controlling figure, but always check the figure that applies to your lot width.
Rear setback. This also scales with lot size, and parts of a building above 4.5 m must sit further from the back boundary. On the smallest lots the rear setback for lower walls starts at 3 m.
The code allows some minor elements, such as eaves and certain fixtures, to sit inside setbacks under set conditions. Corner lots, battle-axe lots and lots with two road frontages have their own variations.
Site coverage: how the code really controls size
Many people expect a simple site coverage percentage. The Housing Code mostly controls bulk in two other ways.
- Maximum gross floor area (GFA). GFA is measured to the internal face of the outer walls, taken 1.4 m above the floor. It leaves out items such as one car parking space and its access, voids and some balconies.
- Minimum landscaped area. A share of the lot must be landscaped, and that share changes with lot size. Each landscaped patch needs to measure 1.5 m or more in both directions to count. A quarter of the landscaped area goes on the street side of the building line, and at least half of the minimum must be behind it.
A wide, sprawling single storey home can run into the landscaping limit before it reaches the floor area cap. Driveways, paths, pools and paved alfresco areas all eat into what is left. If you are going through council, the development control plan may set a site coverage percentage as well.
Building near a side boundary
Planning setbacks are only half the picture. Under the ABCB Housing Provisions, an external wall of a house sitting closer than 900 mm to a side or back boundary must be built to resist fire spread. Openings in that part of the wall, such as windows, must be protected or kept out, apart from some small bathroom or laundry windows set back at least 600 mm. A wall sitting at exactly 0.9 m meets the planning setback and avoids this requirement, but eaves, gutters and fascias need careful detailing.
Checking your numbers early
A detail and level survey comes first. It shows true boundaries, natural ground levels and the houses next door, which the front setback average depends on. From there, a plan assessment tests the concept against the code ahead of paying for full drawings.
You can also read CDC or DA: picking the approval your home project needs if you have not yet settled on an approval path. To get started, see our single storey homes service or request a quote.
Local help across NSW
CertifiBuild certifies Class 1 and Class 10 work in 39 council areas. Local rules on these council pages are a good place to start: North Sydney Council, Bayside Council, Randwick City Council, Campbelltown City Council, Blacktown City Council, Georges River Council.
Suburb pages with local planning notes: North Sydney, Ramsgate, Randwick, Rosemeadow, Schofields, Shanes Park, South Hurstville, South Wentworthville, Stockton, Summer Hill. You can also browse every service area.
Sources
- Housing Code overview, NSW Planning Portal
- Guide to complying development, NSW Planning
- Fire separation of external walls, Part 9.2 of the ABCB Housing Provisions (NCC 2022)