Can I build a granny flat
on my property?
In New South Wales the answer is written into the complying development rules, and it turns on your block rather than your suburb. Enter the address and PiFi reports whether the land allows a secondary dwelling, and the block measurements behind that answer. Outside NSW, read on before you rely on what comes back.
An initial assessment. Speak to a professional before you make any decisions.
This check is New South Wales
Said plainly, because it changes what you get. The granny flat answer PiFi gives runs on the New South Wales complying development pathway, and that is the only state it currently covers. Put an address anywhere else in Australia in and you still get the block itself, its size, frontage and shape, along with the other development paths the land allows. What you will not get is a granny flat answer you can rely on: outside NSW the check has no rules to apply, so read it as unanswered rather than as a no.
Secondary dwelling: the same thing in the rules
Nobody searches for a secondary dwelling, and that is what the planning instruments call it. In Western Australia the term is an ancillary dwelling. Both mean a second, smaller home on the same block as the main house and on the same title, which is what separates a granny flat from a duplex: a duplex is two homes, a granny flat is a main house with a smaller one behind it.
What the block has to give you
Block size
The total area of the land, and the first thing every rule tests. It is also the number most people are confident about and most often wrong about, because a title area and a usable area are not the same thing.
Frontage
The width across the front of the block in metres. It decides whether a second home can be reached and serviced without cutting the main house off from its own yard.
Shape
Whether the block is square or rectangular. An irregular block can clear the area test and still leave no sensible footprint behind the house.
Constraints that change the answer
PiFi checks whether the block carries a flood risk, a bushfire risk, or a heritage listing, and reports each as a constraint on the land. Any of the three can change what a second home has to be built to, and none of them is automatically the end of the idea. They are flags on the block rather than a full assessment, and each is worth raising with your council before you commit to a design.
What comes back
Whether the path is permitted for that block, and the detail behind that answer. This check runs on the New South Wales rules, so outside NSW read the result as unanswered rather than as a no. A granny flat is one of four residential paths PiFi checks in the same pass, so if the block will not take one you will see what else it allows.
Common questions
Can I build a granny flat on my property?
In New South Wales, enter the address and PiFi reports whether the block allows a secondary dwelling under the complying development rules, along with the block size, frontage and shape behind that answer. Outside NSW the check has no rules to apply.
What is a granny flat actually called in the rules?
A secondary dwelling in New South Wales, and an ancillary dwelling in Western Australia. It is a second, smaller home on the same block as the main house, on the same title.
Does the granny flat check work outside New South Wales?
Not yet. The complying development pathway PiFi checks is a New South Wales instrument, so outside NSW the granny flat result is not an answer about your block. An address in another state still returns its block size, frontage and shape, and the other development paths the land allows.
What makes a block suitable for a granny flat?
Size first, then frontage, then shape. A block can be large enough on paper and still have nowhere workable to put a second home, which is why PiFi reports the shape alongside the area.