Home Renovations in WA: When Do You Need Plans, Permits, and a Building Designer?
The number of WA homeowners who start renovation work without the required approvals, and find out the hard way, is larger than most people would expect. Understanding what triggers, a permit requirement before you start protects you, your builder, and your property's sale value.
Home renovation is one of the most common reasons people contact us, and one of the most misunderstood areas when it comes to approvals. What requires a permit, what requires a development application, and what can be done without either depends heavily on the scope of work and your specific council.
What requires a building permit in WA
The Building Act 2011 and the Building Regulations 2012 define when a building permit is required. As a general guide:
• Additions to floor area — any increase in floor area, new rooms, enclosed verandahs, garage conversions, requires a building permit.
• Structural alterations — removing or modifying load-bearing walls, changing roof structures, or altering floor framing.
• New wet areas — new bathrooms, ensuites, and laundries involve waterproofing requirements that are inspected under the permit process.
• Carports, patios, and pergolas — free-standing or attached structures generally require a permit once they exceed approximately 10m² (thresholds vary).
• Decks and elevated structures — structural decks and verandahs require permits due to structural and safety requirements.
What is typically exempt
Non-structural internal work — replacing kitchen cabinets, painting, flooring, and non-structural wall modifications, is often exempt. Like-for-like maintenance and repair is also generally exempt.
When a development application is also required
A building permit deals with construction standards (NCC compliance). A development application deals with planning standards (setbacks, height, site coverage). If your renovation involves an addition that affects setbacks or building height, a development application may be required before the building permit can be lodged.
In practice, this means extensions close to boundaries, second-storey additions, and some carport additions may need planning approval before building approval. We check both requirements as part of our initial assessment.
Why good design matters in renovations
A poorly designed renovation can create problems that are expensive to fix. A recent example: a client came to us after an addition designed by their builder created a dark, internal corridor connecting the new room to the existing house, the natural light from the north-facing living area was completely blocked by the extension. The solution required modifying the roof structure and adding a skylight, costing $12,000 that good design would have avoided entirely.
Common renovation design failures: extensions that reduce light to existing rooms, roof junctions that create water penetration risk, and garage conversions that don't meet NCC ceiling height or insulation requirements.
Frequently Asked Questions
Do I need an energy report for a renovation?
Additions to Class 1 dwellings may need to demonstrate NCC energy compliance, but the requirements differ from new homes. The 7-star NatHERS requirement applies to new homes; additions are assessed under Part 3.12 of the NCC which has different provisions. Your building designer can advise on what applies to your specific project.
How do I find out if my renovation needs a development application?
The starting point is checking your local planning scheme for the setbacks and site coverage limits that apply to your property. If your proposed addition sits within all applicable setbacks and doesn't exceed height or site coverage limits, a DA is generally not required. We carry out this check as part of every renovation project brief.
Can I owner-build a renovation in WA?
Yes, with an owner-builder permit from the Building and Energy Commission (BEC). Owner-builder permits are subject to conditions, including that the owner must intend to live in the home, and carry responsibilities around defect insurance. We work with owner-builders on the design and documentation side of renovation projects.
Thinking about renovating? Book a feasibility conversation, let's work out what you need and the best way to get it done properly. Contact us at projects@fastlanedesign.com.au
