Single storey home certification

Setbacks from the boundary

Side setbacks (the gap to the boundary) depend on lot width. For walls up to 4.5 m high, the setback is 900 mm on lots over 10 m and up to 18 m wide. It is 1.5 m on lots over 18 m and up to 24 m wide, and 2.5 m on wider lots.

On lots from 300 m² to 900 m², the front setback is usually 4.5 m and the rear setback is 3 m. Where two houses stand within 40 m on your side of the street, your front setback is found by averaging the setbacks of the closest two.

How big can the house be?

Floor area is capped by lot size. For example, a lot over 450 m² and up to 560 m² allows up to 290 m² of floor area.

Landscaping is often the tighter limit. You need at least 15% of the lot for lots over 300 m² up to 450 m², 20% up to 600 m², and 30% up to 900 m². Every landscaped strip needs a minimum width of 1.5 m, and half or more of the landscaping must be located behind the building line.

Slab and termites

Footings and slabs must suit the site classification under AS 2870, which rates how much the soil moves (classes A, S, M, H, E and P). Sites rated H, E, P or M-D (deep movement) need an engineer's design. A slab on the ground needs a vapour barrier underneath, with joints overlapping at least 200 mm and pipe holes sealed before the pour.

Where termites are a known risk and the framing can be damaged by them, such as timber, you need a termite system that meets AS 3660.1. Steel, concrete and masonry are not at risk. A lasting notice near the meter box records the system, install date, chemical barrier life and how often to inspect.

Energy rules (BASIX)

From 1 October 2023, the majority of new NSW homes have needed a 7 star energy rating, up from about 5.5 to 6 stars. BASIX also now measures the emissions from making your building materials.

The plans need to show every BASIX commitment. Once the last inspection is done, your certifier arranges a BASIX completion receipt confirming the home was built as promised.

Floor levels and water around the slab

Slab levels set too low are a frequent late surprise on single storey builds. The NCC (National Construction Code) Housing Provisions fix a minimum height for the top of the slab above the finished ground beside it. In most places that is 150 mm. It can drop to 100 mm in low rainfall intensity areas or on sandy, well drained sites, and to 50 mm where the slab adjoins paving or concrete sloping away from the building.

The ground next to the house must also fall away from it. Over the first metre out from the wall, the drop must be at least 50 mm in most cases, or 25 mm for impermeable surfaces such as concrete or clay paving in low rainfall intensity areas.

Stormwater is part of the same picture. Roof and surface water must discharge in a way the relevant authority, usually your council, accepts, and the system must stop overflow in heavy rain from running back into the house. Garden beds, paths and turf laid in the last weeks of a build can quietly undo these levels, so check them against the approved plans before the final inspection.

What counts as floor area?

Under the Housing Code, gross floor area is taken from the inside face of the outer walls, at a height of 1.4 m above the floor. On a single level home, the items that most often push a design over the limit are the garage, the alfresco and any rooms built into the roof space.

Only one car space and its access are excluded from the count, so a double garage adds the area of its second space. Terraces and balconies are excluded only when their outer walls are lower than 1.4 m, which means an outdoor room closed in by full height walls may be counted. Habitable attic rooms are included, while storage basements and areas for garbage and services are not.

Ask your designer to show the floor area calculation on the plans, room by room. It makes the figure easy to check, and it shows early whether a smaller garage or a more open alfresco would bring the design back within the limit.

Step-free entries are a design choice

NCC 2022 contains livable housing design rules, such as a step-free path and entry door. NSW has not adopted them for Class 1a houses, so a new single storey home in NSW does not have to include them.

Many owners still want a level entry for prams, wheelchairs or ageing in place, which must be weighed against the slab height rules. The Housing Provisions let the slab sit as little as 50 mm above hard paving that slopes away from the building. They also allow a smaller 25 mm fall for impermeable access paths and ramps built to the livable housing standard.

A level threshold needs careful detailing of the door sill, the fall on the path and the drainage in front of the door. Settle these details with your designer and builder before the slab is set out, because changing slab levels after the pour is rarely practical.

Does your lot suit the Housing Code?

Zoning comes first. The Housing Code is limited to the residential zones R1 to R4 and the RU5 village zone. Homes in the R5, RU1 to RU4 and RU6 zones are assessed under a separate rural code. The lot must have an area of 200 m² or more and a width of 6 m or more at the building line. Only one dwelling house is allowed on it, plus an approved secondary dwelling.

Battle-axe lots have extra rules. The main part of the lot must measure at least 12 m by 12 m, not counting the access handle. The handle itself must be at least 3 m wide. The handle is also left out when the lot area is worked out, which can lower the floor area and landscaping figures that apply.

Some land is excluded from complying development altogether, including land with Class 1 or 2 acid sulfate soils, land at an aircraft noise level of ANEF (Australian Noise Exposure Forecast) 25 or more, and coastal hazard land. Lots mapped as bushfire prone or flood prone may still use the code under its specific bushfire and flood clauses. Private covenants on the title continue to apply even after a CDC (complying development certificate) is issued.