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Granny flat legislation in New South Wales

The introduction of new development reforms to create more affordable housing and investment opportunities across NSW has renewed interest in secondary dwellings, commonly known as granny flats.

Do I require permission to build a granny flat or secondary dwelling?

You will require building approval for your granny flat or secondary dwelling project where there are two ways to gain this approval. You can lodge a full Development Application (DA) with your local council which is a process that can generally take a number of months. A Construction Certificate (CC) can then be issued by Council or a Private Certifier before construction can commence.

As an alternative to the DA/CC pathway you can engage a private accredited or council certifier and request a Complying Development Certificate (CDC) which is assessed under NSW State legislation. Should your proposed secondary dwelling meet all the required development standards, approval can be issued significantly saving on both time and money.

What will a Certifier do

What will a Certifier do?

As a CDC includes a combined planning and building approval, a Certifier will assess your application for a CDC against the State Environmental Planning Policy (Affordable Rental Housing) 2009 (SEPP) and National Construction Code (NCC 2019) to ensure your proposed secondary dwelling plans comply with relevant legislation, localised environmental plans and Australian Standards. The Certifier will then undertake all the critical stage inspections relative to the development and issue an Occupation Certificate at the end of the job.


Under the SEPP 2009 Schedule 1: Development standards for secondary dwellings, a complying development plan consists of a principal dwelling, and one secondary dwelling.

Some of the criteria listed in the SEPP for a secondary dwelling includes:

  • a principal dwelling either existing, or in the same approval for works application
  • it is to be built on the same lot as the principal dwelling therefore an individual lot in a strata plan or community title scheme does not apply
  • It will be within, attached to or separate from the principal dwelling
  • It has a maximum 60m2 floor area for the secondary dwelling
  • It has a maximum of 1 secondary dwelling per eligible block
  • It is built on an area no less than 450m2 with a 12m street frontage at the building line of the principal dwelling
  • It requires a minimum 3m setback from the rear of the secondary dwelling, and a minimum 0.9m setback from the side boundaries
  • The owner of the secondary dwelling must also be the owner of the primary dwelling
  • A secondary dwelling must be self-contained, with a kitchen, laundry, bathroom and toilet.

Local Environmental Plans

Primarily permitted in residential zones classed R1 through to R5, your local council’s Local Environmental Plan (LEP) may approve construction of secondary dwelling in other zones. Talk to your local council or search for LEP on your local council’s website for information specific to your area.

granny flat standards


Acknowledging the unique climate of NSW, additional compliance in bushfire prone areas is required by the NSW Rural Fire Service. Available on the NSW RFS website, the document, Planning for Bush Fire Protection (PBP) 2019, was integrated into the Environmental Planning & Assessment Regulations in March 2020. For your own peace of mind, you can check your area on the Bush Fire Prone Land Map as you begin the planning process. Save time before hiring a certifier by being aware of whether compliance with the Australian Standard AS3959-2018: Construction of buildings in bushfire-prone areas is required.

Provided the specific criteria of the SEPP 2009 and standards are met, your nominated certifier will issue you with a Complying Development Certificate (CDC) application form. If your property doesn’t meet the minimum requirements set out in the SEPP 2009 for CDC approval it will be necessary to lodge a full Development Assessment application to Council for your secondary dwelling.

When it comes to building a granny flat or secondary dwelling, engaging the services of a company that has years of experience with building legislation and the certification process ensures the experience will be as stress free as possible. Buildcert is the industry leading building approval and private certification service provider.

Buildcert are current members of the Association of Accredited Certifiers (AAC) and our team consists of private building certifiers with trade backgrounds, local government experience and expert knowledge of the building industry’s legislative requirements. Our aim is to provide you with a customer centric streamlined service so that you can get your project started and completed as fast as possible with very few complications along the way.

If you would like us to undertake a CDC Pre-Assessment of your plans for a granny flat to determine whether Complying Development approval is possible please call us on 1300 457 400 or alternatively fill in a request form and one of our experienced team members will be in touch with you shortly.

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