Three storey homes are becoming more common on narrow and sloping lots, where building up makes more sense than spreading out. Whether you can build one depends on the planning controls for your land, not just the design. This guide explains the height limits that apply and the approval path you should expect.
Why the Housing Code usually rules it out
The fastest approval route for a new NSW house is a complying development certificate (CDC) under the Housing Code. NSW Planning describes the code as covering single level and double level homes, and NSW guidance on complying development confirms a two storey limit for dwelling houses. The code also caps building height at 8.5 m, measured from the natural ground.
The code does not count an attic as a storey. Basements have their own size limits and can affect how storeys are counted. A design described as "two storeys over a garage" therefore needs careful checking before you assume a CDC is available.
The usual path: a DA, then a construction certificate
For most three storey houses, the planning approval is a development application (DA) lodged with council, which assesses the design against:
- The local environmental plan (LEP). Many LEPs include a height of buildings map that sets a maximum height in metres for each area. Some areas also cap the number of storeys.
- The development control plan (DCP). DCPs often add wall height limits, upper level setbacks and controls on bulk and overshadowing.
- Merit. Council looks at the impact on neighbours, the streetscape and the site. Neighbours are usually notified and can comment.
Once the DA is approved, you need a construction certificate before work begins. The construction certificate checks the detailed drawings against the National Construction Code and the DA conditions. A three storey house is still a Class 1 building. That means a certifier with Class 1 registration can issue the construction certificate and act as principal certifier.
How height is measured
The Housing Code, like most LEPs, takes building height from the natural ground as it was before any cut or fill. That has two practical effects:
- on sloping land, the downhill side of the house is usually the tallest point, so a lower level built into the slope can push the design over the limit
- raising the ground with fill does not create extra height allowance
Roof form matters too. A flat roof can keep three levels within a limit that a pitched roof would exceed. Your survey needs accurate spot levels across the whole footprint so heights can be checked at each corner.
What changes in the building code
A third storey does not change the building's class, but it does raise the stakes on several technical items:
- Structure: standard framing tables are written for smaller houses, so a three storey frame usually needs more engineering input.
- Fall protection: more windows end up well above the ground, which triggers rules on window openings and balustrades.
- Fire safety: smoke alarms go on every level and must be interconnected.
- Sloping ground: excavation, retaining and drainage become bigger parts of the job.
Our related guides on fire safety and on sloping blocks cover these in more detail.
Checks to do before you design
- get the planning certificate (10.7 certificate) to confirm zoning and any heritage, bushfire or flood controls
- check the LEP height and any storey limits for your land, and read the DCP for your area
- commission a detail and level survey with good coverage of the slope
- have the concept reviewed before full drawings through a plan assessment
For more on the choice between approval types, read CDC or DA: picking the approval your home project needs. To talk about your project, see our three 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: City of Canada Bay, City of Sydney, Hornsby Shire Council, Shellharbour City Council, Camden Council, Penrith City Council.
Suburb pages with local planning notes: Mortlake, Newtown, Normanhurst, Pennant Hills, Potts Point, Shell Cove, Shellharbour, Spring Farm, St Marys, Stanmore. You can also browse every service area.
Sources
- Housing Code policy summary, NSW Planning
- Housing Code overview, NSW Planning Portal
- Guide to complying development, NSW Planning