Dual occupancy developments are one of the most popular ways to maximise land value in Victoria. Whether you are building a second dwelling at the rear of your block or subdividing an existing property, understanding the planning rules is essential before investing in design and documentation.
What Is Dual Occupancy?
Dual occupancy refers to two dwellings on a single allotment of land. In Victoria, this can take several forms — a front and rear dwelling, a dwelling above a garage, or a side-by-side arrangement. The key distinction from a subdivision is that dual occupancy does not always require the land to be split into two separate titles, though subdivision is often pursued simultaneously to maximise the asset value.
The planning system treats each form of dual occupancy slightly differently, and the applicable zone can have a significant impact on whether a proposal is permitted at all, and under what conditions it will be assessed.
Planning Permit Requirements
In most Victorian residential zones, a planning permit is required for dual occupancy. The zones most relevant to homeowners are the General Residential Zone (GRZ), the Neighbourhood Residential Zone (NRZ), and the Residential Growth Zone (RGZ). The GRZ is the most common zone in established Melbourne suburbs — planning permits are mandatory and ResCode compliance is assessed in full.
The NRZ applies in areas where councils want to limit housing density; some schedules prohibit dual occupancy outright. The RGZ, in contrast, is designed to support medium-density development.
- General Residential Zone (GRZ) — planning permit mandatory
- Neighbourhood Residential Zone (NRZ) — may prohibit dual occupancy
- Residential Growth Zone (RGZ) — supports medium density
ResCode: The Design Framework
ResCode (Clause 55 of the Victorian Planning Provisions) sets out the design standards all dual occupancy developments must meet. Key provisions include site coverage (usually capped at 60% of the lot area), permeability (a minimum of 20–30% of the site must remain permeable), and private open space (each dwelling requires a minimum of 40m² with a 3m minimum dimension).
Overlooking and overshadowing are often the most contested aspects of a ResCode assessment. Shadow diagrams must demonstrate that no more than 40% of an existing neighbouring secluded private open space falls in shadow at midday on the September equinox.
Design Tips for Success
From our experience completing over 600 projects across Melbourne, several design principles consistently produce better planning outcomes.
- Orient rear dwelling for north solar access
- Preserve mature trees where possible
- Design accessways at 3.5m minimum width
- Plan for future subdivision from day one