The process

The granny flat approval process in WA

Short answer

Check the lot, fit the design to the 70 m² and setback rules, get planning approval only if the design can't meet them, then prepare the drawings and reports and lodge the building permit. Councils decide within 25 business days on the standard route.

Last updated 29 October 2026

Step by step

  1. Check the lot. Zoning, R-Code density, easements, sewer lines, bushfire mapping and any heritage or estate controls.
  2. Fit the design. Make sure the granny flat is 70 m² or less and meets the setbacks, open space and privacy rules. Small changes here can avoid planning approval altogether.
  3. Planning approval, only if needed. If the design can't meet the standard rules, we prepare and lodge a development application first.
  4. Drawings and reports. Floor plans, elevations, sections, engineering, an energy efficiency assessment and a BAL assessment if the lot is bushfire-prone.
  5. Building permit. We lodge the application, either the standard route (council checks it) or the certified route with a private building surveyor's certificate.
  6. Build and inspections. Your builder builds it, and the council may inspect along the way.
  7. Finish up. Once complete, the builder lodges a notice of completion and the services are connected.

How long it takes

StageTypical time
Checks, design and documents2 to 4 weeks
Planning approval (if needed)About 6 to 8 weeks, sometimes longer
Building permit, standard routeUp to 25 business days after lodgement
Building permit, certified routeUp to 10 business days after lodgement

Builder, kit or modular?

A registered builder will often handle the permit as part of the build. With a kit or a modular granny flat, the permit is often left to you. That is where we come in: we take the supplier's drawings and engineering and turn them into a complete application for your lot.

Questions

Common questions

Do I need a registered builder for a granny flat?

In WA, building work for someone else worth over $20,000 generally needs a registered building contractor. Owner-builders need an owner-builder approval first. Ask us if you're not sure which applies.

Can you help with a modular or prefab granny flat?

Yes. Modular granny flats still need a building permit for your lot, covering the footings, connections and placement. We prepare it from the manufacturer's documents.

A granny flat is a big project. The paperwork shouldn't be.

We check the 70 m² rules, line up the drawings and engineering, and lodge with your council. You get one point of contact from start to permit.

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