What Boundary Setbacks Are Required for a Granny Flat in NSW?

Written by Granny Flat Builder | Sep 15, 2026

In NSW the planning legislation is clear - Granny Flats are a welcome addition to housing stock across the state. There is specific legislation, updated in November 2021 (the Housing SEPP) that sets out the guidelines for being able to build a Granny Flat with NO council approval, including what set backs are required for your lot size. Here we cover in detail how close you can build a Granny Flat to your boundary and to other structures on your site.

Complying development certification (CDC) is a faster approval process which ensures planning and environmental requirements are met through a set of prescribed approval conditions. An application for a CDC can be lodged with either a local council or an accredited certifier acting as the Certifying Authority. At Aplus we will work through how to build your Granny Flat with NO council approval to get a faster, smoother Granny Flat build. Here is some of what we will look at.

Zoning for Granny Flats

Granny Flats are permitted in residential zones (R1, R2, R3, R4 under a CDC and R5 under a DA). They may also be permitted in other zones under a council’s local environmental plan.

Classification of Granny Flats

A Granny Flat is a secondary dwelling. There can only be one principal dwelling and one secondary dwelling on each property. It is possible to build, two Granny Flats on a property however one of these would be classed as a main dwelling. The Housing SEPP provides for a new principal and secondary dwelling to be approved under a single complying development certificate.

Minimum Site Area for Granny Flats

The minimum site area is 450m2. If the land has an area less than 450m2, the development cannot be carried out as complying development regardless of whether it is attached to the principal dwelling. An exception to this is where a secondary dwelling is located entirely within an existing dwelling house.

Maximum Floor Area for Granny Flats

The maximum floor area for granny flat is not mentioned under this title. The maximum floor area, measure from the outside of the external wall is 60m2.

Building Clearance

1.8-metre clearance between class 1 buildings. You can build closer to class 1 buildings providing the relevant wall/s within 1.8 metres are fire rated. It is important to note that you can build as close as 1000mm to other structures such as garages providing garage is at least 1.8 meters away from primary dwelling.

Setbacks for Granny Flats

The setback of a site with a front boundary on a primary or parallel road is equal to the average of the front setbacks of the nearest two dwelling houses on the same road. These dwelling houses must be located within 40 metres of your lot. Otherwise, the setbacks are based on the lot size as shown in the diagrams below. There is a minimum setback of 3 metres from the rear boundary, 900mm from the side boundary and 4.5 metres from the front boundary. Click to view each setback guideline.

Knowledge is non-negotiable. Our Design Consultant will measure out your site and help you fully understand the possibilities for your block, and be able to discuss in detail your options for a CDC or Development Application. When you’re planning to build, you want assurance that your site is suitable, and that you are not going to be impacted mid-build by unforeseen or surprise costs. We provide a thorough, free, upfront feasibility study for your Granny Flat which gives you an assured green light to build.

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