On a triplex site, the homes may be separate buildings, but the land under them is shared. Driveways, drainage and service routes have to work for three households, often on a lot that was designed for one house. Planning these early avoids redesign and title problems later.
Driveways and car access
A shared driveway usually runs along one side of the lot. Council's development control plan and the Australian Standard for off-street parking set the width, gradient, passing bays and turning space. Many councils require cars to drive out forwards rather than reverse onto the street, and that needs room to turn.
Think about:
- where visitors park and where bins are stored and collected
- how the driveway drains, so runoff does not flow into garages
- lighting and letterbox locations for each home
- on bushfire prone land, the Rural Fire Service requirements for access
If the site will be subdivided, the driveway becomes common property under strata, or is covered by a right of carriageway under Torrens title. Either way, the approved plans should include it.
Water, sewer, power and gas
Each home generally needs its own metered water supply, its own sewer connection and its own electricity supply. The water authority sets the rules for meters and connections, and its approval is often needed if you build over or near a sewer main. Service routes should be planned so that a future boundary does not leave one home's pipes running under another's lot without an easement.
Running services through separating walls
Where services pass through or along the walls between homes, the building code applies. Under the ABCB Housing Provisions:
- openings for services in a separating wall are limited in size and must be packed with fire-resisting material
- power points and switches that face each other through the wall must be spaced apart, or kept shallow
- a water pipe serving one home must not be fixed to the wall leaf on the neighbour's side, and needs at least 10 mm clearance from it
The simplest approach is to route services so they do not cross separating walls at all. Our guide on The separating wall between duplex homes: fire and sound rules covers the wall itself in more detail.
Stormwater and drainage
Three roofs and a long driveway create a lot of runoff. Council may require on-site detention, and the system usually drains to the street or to an easement over a lower neighbour's land. If a drainage easement is needed, start the conversation with that neighbour early, because it can take time.
Stormwater connections are a mandatory inspection stage before they are covered. Leave the pipework exposed until the principal certifier has inspected it, and book at least 48 hours ahead through our inspection booking page.
Getting it on the plans
Shared elements are easy to leave vague at concept stage and hard to fix later. The approval plans should show the driveway, bin store, service routes, meters, stormwater layout and any easements. Our plan assessment service can check those details before lodgement. See our triplex page for more on how we certify these projects.
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: Blue Mountains City Council, Central Coast Council, Sutherland Shire Council, City of Parramatta, Wollondilly Shire Council, Ku-ring-gai Council.
Suburb pages with local planning notes: Blaxland, Booker Bay, Caringbah South, Carlingford, Douglas Park, Gymea, Lindfield, Lugarno, Macquarie Pass, Marsfield. You can also browse every service area.
Sources
- Separating wall fire rules (Housing Provisions Part 9.3), ABCB
- Sound insulation of separating walls (Housing Provisions Part 10.7), ABCB
- Low and mid-rise housing policy key provisions summary, NSW Department of Planning