Do Granny Flats Need To Comply With BASIX?

Building a granny flat in New South Wales (NSW) is a popular way to add value to your property or support multigenerational living.

But many homeowners don’t realise that BASIX compliance is a key part of the approval process.

As a town planner in NSW, I regularly help clients navigate this step as part of their DA approval or CDC application.

What Is BASIX and Why Does It Matter?

BASIX stands for the Building Sustainability Index. It’s a mandatory NSW Government requirement designed to improve the environmental performance of residential buildings.

If you’re submitting a development application for a secondary dwelling (commonly known as a granny flat), you’ll almost always need a BASIX certificate.

This applies whether you're going through the DA pathway or a complying development.

The requirement kicks in for any new residential structure over $50,000 in estimated cost. Since most granny flats exceed this threshold, BASIX applies.

Planning Advice for Granny Flat Projects

As a planning consultant, I often see confusion around when BASIX is required. For example, a client recently assumed their 55-square-metre granny flat wouldn't need a certificate because of its small size.

However, NSW building regulations don’t exempt small dwellings from sustainability requirements.

We provided planning advice, coordinated with the architect, and included the BASIX certificate in the council submission for secondary dwelling NSW.

The key is integrating all planning elements early. This includes understanding energy use, water fixtures and thermal comfort, all of which are assessed in BASIX.

Town Planning Services for Residential Development in NSW

Our firm offers town planning services for residential development NSW clients can rely on.

We prepare the statement of environmental effects for NSW DA, handle the BASIX process, and ensure all documents meet NSW planning standards.

Whether you’re building in a standard residential zone or a heritage area, your granny flat project must comply.

In heritage zones, we also prepare heritage impact statements NSW town planning authorities require, alongside BASIX and DA documentation.

Getting Council Approval Without Delays

For any DA involving a granny flat, getting your planning permit NSW approved smoothly requires a full, compliant package.

This includes your architectural plans, BASIX certificate, environmental impact assessments, and in some cases, an expert help with Clause 4.6 variation request NSW.

Each LGA may apply the DCP differently, so working with a town planner near me specialising in NSW DCP can save weeks of back-and-forth with council.

We recently assisted a homeowner in the Northern Beaches LGA who was adding a secondary dwelling above an existing garage.

Along with their development application, we prepared their BASIX and energy modelling, resulting in a fast council approval.

Final Tip: Start With the Right Planning Advice

If you’re wondering how to get a DA approved in NSW, don’t leave BASIX compliance to the end.

A qualified NSW town planning consultant for subdivision approval or dual occupancy can guide you through the process.

Whether it’s a granny flat, a commercial change of use, or a dual occupancy, your application is only as strong as your planning documentation.

Getting the planning advice for dual occupancy NSW residents trust can make all the difference.