How to get planning approval for an extension in South Australia

Every extension in South Australia needs a planning consent and a building consent. The planning consent assesses whether the extension is acceptable in principle: does it comply with setback rules, height limits, site coverage, streetscape, overshadowing, and overlooking. The building consent assesses whether the extension has been designed and detailed to a standard that meets the National Construction Code, the Building Code of Australia and Australian Standards for structural, fire and health performance.

These are separate assessments, often carried out by different people, sometimes on different timelines. A designer can lodge them together as a bundled application to save time. In practice, planning consent is usually the longer of the two, because it involves subjective judgement about design merit.

Both consents are lodged through the state PlanSA portal, but the assessment is delegated to your council for planning consent and to either the council or a private certifier for building consent. You can choose to use a private certifier for the building side to speed things up. On the planning side, your council is the only assessor.

Every Adelaide council offers a pre-lodgement meeting with a duty planner, either free or for a nominal fee. This is the single highest-leverage step in the approval process. Bring your survey, your massing sketch, and clear photographs of the existing home and both neighbouring properties. Ask the duty planner three questions specifically.

First, is the extension likely to be assessed as deemed-to-satisfy (a fast, technical assessment against the Planning and Design Code) or performance-assessed (a more subjective merit assessment)? Deemed-to-satisfy applications are typically decided in four to six weeks. Performance-assessed applications can take twelve to twenty weeks.

Second, is the extension likely to trigger public notification to neighbours? Notification is required when the extension varies key setback, height or overshadowing rules significantly. It adds four to six weeks to the process and gives adjoining owners a formal right to object.

Third, are there any local overlays that apply to your site: Historic Area, Character Area, Heritage-listed, or Environmental. Each overlay imposes additional criteria and typically requires a Statement of Effect explaining how the extension responds to those criteria.

A planning application in South Australia typically needs the following drawings and documents: a site plan showing setbacks and overshadowing to neighbours; existing and proposed floor plans; existing and proposed elevations; a landscaping plan for larger extensions; a Statement of Effect if the application is performance-assessed; a site cross-section showing floor levels relative to the street; and photographs of the streetscape context.

For heritage or character overlays, add heritage impact statements, materials and colour schedules, and detailed elevations showing how the new work sits alongside the original.

A skilled residential building designer or architect will assemble this package as part of their fee. Attempting to lodge without a designer is possible in theory for very simple extensions, but the council refusal risk rises sharply. The design fee is typically a small percentage of the total build cost and pays for itself in reduced approval risk.

If your extension triggers public notification, the council will write to your immediate neighbours and give them a defined window, usually ten business days, to lodge a representation. If neighbours object, the application typically moves to an Assessment Panel hearing, which adds weeks and sometimes requires you or your designer to attend.

The strongest strategy is to talk to your neighbours before you lodge. Show them the drawings, walk them through the overshadowing analysis, and answer their questions. A letter of support from a neighbour, or simply a signed indication that they have seen and understood the design, materially reduces objection risk.

If a neighbour has genuine concerns about privacy or overshadowing, changes at design stage (a smaller upper-floor window, a repositioned window with obscure glass, a small roof-line adjustment) are almost always cheaper than fighting through an Assessment Panel.

Once planning consent is granted, the building consent process begins. If you used a private certifier for the building side and bundled the lodgement, this can be a fast follow-through. Building consent typically checks structural adequacy, energy efficiency compliance under NatHERS, fire separation to adjoining properties, and health provisions such as bathroom ventilation and glazing safety.

Development approval is issued only when both planning consent and building consent are granted. This is the document that allows the builder to actually start on site. Do not schedule demolition, site set-up or trade start dates until you have development approval in hand.

A final procedural note: essential safety provisions and any conditions attached to the planning consent must be captured in the construction contract with the builder. Otherwise there is a risk of building work that technically breaches the consent, which becomes a headache at Certificate of Occupancy stage.