What is an Attached Granny Flat?

Written by Granny Flat Builder | Sep 15, 2026

Have you always wanted to enjoy the financial benefits and lifestyle advantages of a Granny Flat on your property, but have limited backyard space? Attached Granny Flats (sometimes referred to as a dual living design) are a great option for accommodating older children, extended family, guests, renters, live in nannies and, of course, grandparents!

In this article, we unpack a few key facts about what exactly qualifies as an attached Granny Flat, and why they are such an attractive option.

What is the definition of an Attached Granny Flat?

According to the Affordable Rental Housing State Environmental Planning Policy (NSW) 2009, a Granny Flat or secondary dwelling is referred to as a self-contained dwelling that is erected on a property in conjunction with another dwelling (the principal dwelling), and can be either attached to or detached from the principal dwelling.

A granny flat is considered ‘attached’ once it is within 900mm from the principal dwelling.

What are the benefits of an Attached Granny Flat?

For both savvy investors and family-oriented homeowners, Attached Granny Flats bring a wide range of benefits:

An Attached Granny Flat can work well for smaller blocks of land such as homeowners who live closer to the city, or for those who want to keep as much of their garden space as possible.
They provide that added level of security, supervision and closeness, for accommodating family members that are ageing, have a disability, or just generally need a little extra support.
Preserve your privacy while comfortably hosting guests or relatives, and reap the benefits of built-in babysitters!
It provides functional, versatile space that can even be used as a home office, allowing remote workers to join video conferences in a peaceful, professional and private manner. Plus, every Attached Granny Flat built by APlus includes the very latest in Wi-Fi technology as standard.
APlus Attached Granny Flats can be completely customised to suit your needs and tastes. For example, you can add wheelchair ramps and wider doorframes, extended outdoor decking and alfresco areas, or you can even design your Granny Flat to match the look and feel of your existing property.
Add substantial value to your existing property, and establish a regular form of passive income if you choose to lease the Attached Granny Flat. In today’s agile world, there are also more casual income opportunities at your disposal such as short-term Airbnb renting.

Are there any rules about what an Attached Granny Flat can and cannot include?

The Nation Construction Code (NCC) requires all Granny Flats to include a kitchen, a bath or shower, clothes washing facilities and a toilet. Another important requirement to help stop the spread of fire from one dwelling to another is a wall with an FRL (Fire Resistance Level) of not less than 60/60/60, or a masonry wall not less than 90mm thick, between the Granny Flat and principal dwelling

It is also preferred that there is no internal access between the Granny Flat and principal dwelling. If a door is provided, it would be need to be a self-closing door with solid core and a thickness of no less than 35mm.

Are there any advantages to building an Attached Granny Flat in the next few months?

Your attached Granny Flat could be achievable within a Complying Development Certificate (CDC), however, observing that the choice of an attached Granny Flat is often due to space, it will often need to be approved via a development application (DA). With most councils will be working through a backlog of building requests, the sooner you start the process of working out what is possible - the sooner you will get approved and get ready to create this special new space for your family.

Reference:

https://treasury.gov.au/sites/default/files/2020-06/Fact_sheet_HomeBuilder.pdf

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