Granny Flats and
Home Additions

Your trusted Perth builder

Move-in ready, customised granny flats.

Call today for a free consultation
08 9329 6888


Move-in ready, customised granny flats.

Call today for a free consultation
08 9329 6888

Granny Flats WA – Home Extensions & Renovations

Granny Flats WA is a Family owned and operated residential Building company having serviced the Perth metropolitan area for over 20 years.

Granny Flats WA has long been a trusted builder of Granny Flats in Perth, Western Australia. We have many years experience and the necessary knowledge to provide you with a beautiful finished product you can be proud of.

We see granny flats as micro homes in your backyard that we build from concrete slab to finished structure. Every home is different regarding privacy, lighting and existing structure particulars. Our trained building & design consultants listen to your needs and wants. They can make an obligation free visit to your home to advise you on which granny flat features would suit you best. 

In addition to building granny flats, we also build renovations and extensions. We can do everything from a small studio or office to a complete home renovation. We can help you transform a home with two bedrooms and one bathroom to a home with five bedrooms, three bathrooms, a pool and al fresco.

Some of our clients like building in stages. We can accommodate that by building a locked up structure with the necessary allowances for pre-lay plumbing. This allows the client to elect when to proceed with adding a bathroom, kitchen, laundry and decorations as their budget and needs require. Our experienced design consultants ensure that any local council approvals are organised.

Our granny flats can suit a variety of different purposes. They are great guest houses if you have friends or relatives visiting from out of town. They work well as home work spaces or hobby rooms. You can use one as a residence for your children or parents. Recently, laws have changed to make them great rental properties as well. People can now derive an income from renting out granny flats in their backyards. We have seen an increase in interest from investors and have some great testimonies.

Our showroom showcases some of the granny flat designs and renovation options we can provide. Bring the family and have a look at what’s available.

Wooden deck and exterior of grey granny flat. White alfresco dining chairs and light coming from inside the granny flat.


Interior of granny flat with white kitchen counter, silver stove and white dining table in background

Granny Flats WA is a Family owned and operated residential Building company having serviced the Perth metropolitan area for over 20 years. We provide a tailored personal service including:

  • Design Consultation & Advice
  • Drafting
  • Energy Efficiency
  • Engineering
  • Council Submission through both Planning Department and Building Departments as required
  • Pre-Start Service
  • Quantifying, Ordering & Scheduling
  • Construction
  • Warranties

Granny Flats FLOOR PLANS

Open plan living and kitchen area with red couch, red carpet, wooden kitchen cabinets, stove, black wooden dining table and wooden coffee table
bedroom with hardwood floor, white bed, ceiling fan, blue curtains, wooden blinds and ceiling fan
White kitchen with wooden floor, silver fridge, white kitchen cabinets, stove, glass dining table and white chairs with door in background
Illuminated kitchen with wooden floor, two separate white countertops, red stand mixer and window
wooden floor with piano and rows of shelving holding books and other decorations

Book an appointment for a free consultation


Based south of the river in Booragoon our show room offers 3 indoor granny flat displays.
Phone: 08 9329 6888

Address: 92 McCoy Street Booragoon Open: Mon – Friday: 9am to 4pm Saturday 10am to 12.30pm

We are happy to arrange a time to meet at the showroom after open hours, anytime suitable to your availability.


FAQs ABOUT Granny Flats

A granny flat (or ancillary dwelling) is a self-contained living space built on the same block as an existing house. The structure can be attached to a home or be freestanding. They are self-reliant, with their own sources for utilities.

Granny Flats WA build in the Perth Metro and surrounding suburbs.

Granny flats can be built at a variety of price points depending on the size and specifications you choose. A budget one-bed investor specification granny flat can be built from as little as $130,000 move-in ready. On the other end of the spectrum a granny flat can cost more than $275,000 for a designer, very large granny flat that has carports, garages, verandas etc.

Granny flats will no longer require planning permission from local councils in WA as of April 2024. Previously, planning permissions had to be submitted to local councils before building a granny flat. However, other approval criteria such as building permits are still necessary to ensure your granny flat is built to a high standard that will be safe for any occupants. Our dedicated talks about granny flat approvals in more depth.

For Granny flats up to 70sqm it would take approximately 10 weeks to build from slab down to complete including painting, floorcoverings, skirting boards, blinds and air-conditioning. Granny Flats WA will take care of all council approvals as part of the pre-process which will vary the time to build depending on local council approval processes.

Under the standard R Codes, granny flats can be built on a single residential property over 350sqm in Western Australia. Considerations for setback and parking need be considered and in certain councils additional restrictions will apply.

Yes, granny flats add value to a home. The added value will be relative to the location, design and the state of the residential property market at the time. We delve deeper into this topic in our blog post here.

Yes, granny flats can be two-storey if the total living space does not exceed the council allowance (70m2 in most councils). Due to the current busy building climate, Granny Flats WA is not building two-storey granny flats at the moment.

The minimum total block size required for a granny flat is 350m2. Our minimum recommended size for a liveable granny flat is 20m2 or 30sqm with a separate bedroom. A granny flat of this size would require an open space of 42m2 to have a 1 metre setback from each exterior wall.

In residential areas, the maximum size allowable for a granny flat is 70m2 as per the Residential Design Codes. On larger blocks and more rural areas, granny flats can be built up to a maximum size of 100m2. If for any reason you would like to build a granny flat in Western Australia bigger than these limits, with good reason, there are ways to go bigger.

You are not able to build a granny flat on a vacant lot. A granny flat must be built on a lot where there is an existing house. It can not be the first piece of property built on an empty piece of land.

You can not build more than one granny flat on a single lot.

Firstly a granny flat design needs to suit the purpose of the build whether it be for mobility, downsizing family or rental. Also designing to complement the existing residence avoiding clashing entertainment areas and windows looking directly to the existing home. This design service is provided free of charge after a showroom visit.

Granny flats act as ancillary dwellings consisting of a bedroom, kitchen, and bathroom. Granny flats can either be freestanding or attached to the existing house. Studios and Bedsitters are granny flats with a bedroom, living area and kitchen in same open living space.

Yes, we can convert garage spaces to granny flats. As a rough guide a garage conversion has a similar cost to a freestanding granny flat but will require individual quoting depending on the existing structure. Read our blog post on converting a garage to a granny flat for more information.

Granny flats can be rented out. Laws have changed in WA over the last few years to allow for granny flats to serve as rental properties. However, they must go through all the necessary approval processes.

Some present examples we have been notified of for rental are around $250/week for a single bedroom granny flat in Quinns Rocks. Again the net rental attained will be relative to location, number of bedrooms and finish. A 70sqm granny flat is the same living area as a new home on a cottage block. So, there is no reason the value of rent from granny flats would not be similar to that of same size houses in the same suburb.

As a specialist builder of Granny Flats we work with our clients to design bespoke builds suitable to each client’s needs. We do have several pre-designs from which we can adjust, however all designs are individual incorporating any special needs such as considerations for mobility or open plan one, two or 3 bedroom customised granny flats.

A lot depends on how much space you have – we can then offer a custom design. All our granny flats are designed based on your needs.

We build in ranges, from the investor rental design or standard specification, right through to our executive apartment specification as shown off in our showroom in Booragoon (also our head office). We always suggest a showroom visit to view our granny flat designs and consultation prior to visiting the home. This will give you the best information for discussion when on site.