Got your heart set on that dream extension, only to have council knock it back? Well then you’re not alone, that’s for sure. Every day in Perth councils knock back extensions, renovations and plans.

Even the ones you think are perfectly reasonable. But a lot of these rejections could also be avoided with better planning from the beginning.

I’ve been working in town planning around Perth for over a decade now and honestly the same mistakes keep coming up again and again.

What’s frustrating is that most of these rejections aren’t because the projects are fundamentally flawed its they’re because someone didn’t understand how Perth councils actually assess applications.

Actually, let me walk you through the five biggest traps that catch homeowners and their builders off guard. Knowing about these before you get started on your project, big or small, they can save you months of delays and thousands in costs.

Mistake 1: getting the setback requirements wrong

This one catches people often and it doesn’t just mean checking the plan. Different areas of Perth have different setback rules and some of them are confusing if you haven’t dealt with them before.

I had a client last year who wanted to extend their kitchen in Mount Lawley. Seemed simple enough they had plenty of backyard space and no neighbours complaining. But they got knocked back because their extension was 50cm too close to the rear boundary. The builder had does their calculations for the setbacks based on what they’d done in other suburbs But Mount Lawley has special requirements. They have different requirements than regular R code that most suburbs have.

One thing that I hav eto mention though Is that different councils actually measure setbacks differently. For example The City of Stirling, can be pretty particular about how they measure from irregular boundary lines. I’ve seen some project applications get rejected because someone measured from the wrong point on a curved boundary.

And don’t get me started on corner blocks. The setback rules for corner sites in places like Fremantle or the City of Perth can be completely different from what applies to regular blocks. Theres a big possibility that you’ll need to get bigger setbacks and that you might not be able to put windows or entrances and driveways wherever you want, there may be specific rules you have to follow.

Mistake 2: ignoring you’re neighbours

This is where a lot of people get themselves into trouble and it’s usually because they think planning applications are just about meeting technical requirements. Wrong.

Politics matters, especially in Perth where neighbourhood character is a big deal for many councils.

You might have every right to build your extension without talking to neighbours first. Your plans might meet every single planning requirement. But if Mrs Johnson next door decides she doesn’t like your extension and puts in an objection then suddenly your straightforward application becomes a lot more complicated.

Perth councils take neighbour objections seriously, particularly around issues like privacy, overshadowing, and visual impact. Even if your extension technically complies with all the privacy rules, a well written objection from a neighbour can make council take a much closer look at your application.

I remember a time in Subiaco when a family put in an application for a second story renovation. The plans seemed fine and they had met all the requirements they needed to like height and setbacks.

But three different neighbours objected saying it would look into their backyard and just like that council knocked it back. They eventually passed it when they added in extra screens for privacy but it wasn’t what the client originally wanted which was a little disheartening.

Of course, this depends on your neighbours too. Some people are reasonable, some are easy going and some are the opposite. You know the type.

Mistake 3: underestimating Perth’s heritage and character requirements

This one’s becoming a bigger issue as more of Perth gets heritage listings or character protection overlays. What used to be straightforward residential areas now have additional planning controls that can catch people completely off guard.

The heritage requirements aren’t just about obviously historic buildings either. Heaps of ordinary houses form the early mid 20th century are now considered to have heritage or character value. If your house is in one of these areas, your extension needs to be sympathetic to the existing building style and the broader streetscape.

The heritage requirements aren’t always clearly defined. Council might say your extension needs to be “compatible with the character of the area” but what does that actually mean in practice? Different council officers might interpret these requirements differently, which is pretty annoying.

I worked on a project in Cottesloe recently where the client wanted to add a modern glass extension to their 1940s weatherboard house. Beautiful design, well thought out would’ve looked fantastic. But council knocked it back because the materials and style were too contemporary for the heritage area.

Mistake 4: getting the parking and access calculations wrong

Perth councils are really particular about parking requirements and the rules are more complex then most people realise. It’s not just about having enough car bays it’s about where they’re located, how you access them and whether they meet the technical requirements for size and gradient.

The number of parking spaces you need depends on how many bedrooms your house will have after the extension. Add a bedroom, you might need an extra car bay. But here’s where it gets complicated sometimes councils count studies or large living areas as bedrooms for parking purposes, even if you don’t intend to use them that way.

I’ve seen applications get knocked back because someone added what they thought was a home office, but council classified it as a bedroom and required additional parking that couldn’t fit on the site. Frustrating doesn’t even cover it.

Then there’s the access requirements. Your driveway needs to meet certain width and gradient standards. If your extension affects getting to existing parking you might need to redo your whole driveway layout. Sometimes that means moving crossovers, which requires separate approvals and can cost thousands.

Mistake 5: overlooking stormwater and environmental requirements

This is the one that’s become a much bigger deal in the past few years, and it catches heaps of people off guard because it wasn’t such a big issue in the past.

Storm water management is a serious problem to Perth councils nowadays so taking it seriously is in your best interest. If your extension plans mean more hard surfaces on your property you may want to show how you will manage the run off.

You may have to install rain tanks and retention systems or even paving that is permeable. You could just have to show that your rain tank works properly or can drain water without leaking into your neighbours yard.
The environmental requirements are getting stricter too. If you’ve got significant trees on your property, your extension might need to be designed to protect them. Perth councils have become much more protective of mature trees particularly natives.

Perth planning approvals

Planning approval for home extensions in Perth doesn’t have to be a nightmare, but it does require understanding how the system actually works rather than how you think it should work. The councils aren’t your enemies, but they’ve got rules to follow and community expectations to manage.

Planning doesn’t just mean checking off a list, you need to take the time to research your specific council requirements. It will make your life easier during this already stressful process. It will mean you don’t miss anything and you also make sure everything matches the requirements.