Can I Build a Duplex on My Land in NSW?

Building a duplex is a popular way to maximise land use, increase rental income or accommodate extended family.

But whether you can build one depends on several NSW planning factors, including zoning, lot size and council controls.

As a town planner NSW based, I’ve worked with many clients unsure if their land qualifies.

While duplexes are allowed in many residential zones, they’re subject to strict design, parking and amenity rules.

Getting the right planning advice early makes all the difference.

Check Your Zoning and Lot Size

The first step is checking your property’s zoning under the local LEP (Local Environmental Plan).

Most R2 Low Density zones allow dual occupancies with a development application. Some areas also permit duplexes as complying development if specific criteria are met.

For example, one client in Penrith had a 650-square metre block zoned R2.

With the right setbacks, open space and minimum frontage, the site met the requirements for a development application.

We assisted with the council submission for secondary dwelling NSW approval and prepared a statement of environmental effects for NSW DA to support the project.

A planning consultant can confirm whether your lot meets the minimum size and frontage under the DCP, and whether the proposal complies with NSW planning policy.

DA Approval or Complying Development?

In some cases, a duplex can be built as complying development, which avoids the full DA process.

But only if the site isn’t flood-affected, bushfire-prone or in a heritage area.

We advised a client in Parramatta who assumed complying development was an option.

But after reviewing overlays, we identified a heritage item nearby that triggered a heritage impact statement NSW town planning review.

This meant the project required a full development application.

Knowing how to get a DA approved in NSW means addressing these constraints clearly in your submission.

This often includes design justifications, privacy diagrams and sometimes expert help with Clause 4.6 variation request NSW if setbacks or height slightly exceed controls.

Design, Parking and Amenity

Duplex designs must meet building regulations NSW councils enforce, including fire separation, acoustic insulation and private open space.

Off-street parking for both dwellings is often required.

Our in-house drafting team recently worked on a duplex design in Campbelltown where tight street width made standard parking access tricky.

With early planning advice and input from council, we adjusted the layout to ensure council approval without needing a redesign.

If you're planning to subdivide the duplex later, you’ll also need advice from a NSW town planning consultant for subdivision approval.

Get Expert Town Planning Advice Early

Every council has its own approach.

A town planner near me specialising in NSW DCP can guide your project from feasibility to DA approval.

We deliver town planning services for residential development NSW wide, including planning advice for dual occupancy NSW sites.

Whether you’re investing, downsizing or building for family, starting with a clear strategy saves time and money in the long run.