Thinking of building a Granny Flat? Here's what you need to know.

Perhaps you would like an elderly relative to be nearer you whilst keeping their independence,  or you want more space for young adults or teens in the family. Maybe you see the potential to make some extra income.  Whatever the reason, more and more Australians are considering building a second dwelling, AKA, the 'Granny Flat'. 

What is considered a 'Granny Flat'?

'Granny Flat’ is a simple catch-all term that is generally used to define a secondary, non-attached second dwelling on your property. They are, of course, not solely reserved for your grandma, but are an increasingly popular feature as people look for alternative ways to add space and value to their homes. To be considered a ‘true’ second dwelling, the structure must be certified by a builder, and be a fully functioning, self-contained home. Specifically, this means that the home should have at least one bedroom, full cooking facilities and space i.e a kitchen or kitchenette,  as well as a living area, bathroom and laundry facilities. How one lays these out is very much determined by building codes (more on that later) and your personal preferences. 

How are they made?

The secondary dwelling will be smaller than the original dwelling.  In Queensland, councils refer to Granny Flats as ‘secondary dwellings’ which can be a maximum of 80 square metres in size (not including patios and car space). There are as many build options for a granny flat as there are for a conventional home,  perhaps even more. They are available as pre-built modular homes, flat packs (that you put together yourself), shipping container conversations, barn conversations, cabins and even yurts. The list goes on and on and is guided by your imagination and budget and codes.  However, it is a good idea to keep the new development in keeping with the style of the main dwelling as this consistency will look good (and likely add value) to the home when selling. Simply put, the secondary dwelling will almost always be smaller than the original dwelling.  

Do I need planning Permission? Yes and No...

if the intended resident of the new dwelling is a family member or genuine member of the household, then you technically do not have to seek planning approval. However, this does not mean that you can just go for it! This development might not need planning approval but will need to be up to code. For example, Brisbane Council states that “Certain types of projects do not need a development application but must comply with Brisbane City Council’s planning rules, including applicable codes. These projects are referred to as "accepted development, subject to requirements". This is important to understand: if you fail to build to code it could be costly to rectify or worse, may result in you having to pay for the removal of the dwelling. 

You will need to seek planning permission if any of the following apply:
  • The secondary dwelling will be more than 20 metres from the main residence.
  • The granny flat is bigger than 80 square metres in size.
  • You are going to rent this property to someone who is not part of your household.
How much space do I need to build? 

It goes without saying that you will need enough space on your existing lot to actually build the second property. Councils have rules regarding the maximum proportion of the site that is allowed to be covered by buildings. This includes both the main house and granny flat and other structures.

  • 50% for lots 400 square metres or more.
  • 60% for lots 300 square metres or more and less than 400 square metres.
  • 70% for lots 200 square metres or more and less than 300 square metres.
  • 80% for lots less than 200 square metres.
Next Steps: 

As we recommend at Pest Build Legals, always speak to a professional. A good place to start is by speaking to a good local builder. He will have insight into what can be done with your land and in the area generally. At the same time, contact your local council for more information about building secondary dwellings in that council. If it all checks out - go for it! A granny flat is a valuable addition to any property and can bring families closer together. If built to code and with permissions, it can be a sound investment that can give you an additional income stream whilst still enjoying your own home.

Written by Ben Saravia,  

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