rhys@rdbd.com.auEmail | Call 0414 135 014 | Altona Victoria
Floorplan for duplex development

Townhouse and dual occupancy design. Multiple dwellings, one site

Building designer for multi-unit development across Melbourne's western suburbs

Most residential blocks in Melbourne's western suburbs are carrying a single dwelling on land the planning system will permit to hold two or more. A dual occupancy or townhouse development, designed and permitted properly, turns that potential into rental income, a separate title to sell, or a home for family on the same block as your own. We take multi-unit projects from initial site assessment through to approved construction drawings and a complete permit set.

Dual occupancy and townhouse design. What is the difference

Dual occupancy means two dwellings on one block, commonly called a duplex. A townhouse development involves three or more attached dwellings and generally requires strata or community title subdivision, with correspondingly more detailed planning scrutiny around setbacks, overlooking, private open space, and streetscape impact.

Both project types are worth understanding before committing to one. The right answer depends on your site, your council's planning scheme, and what the development needs to achieve financially.

Can you subdivide your property

It depends on your block. Minimum lot sizes, frontage requirements, council overlays, and vegetation protections all shape what is achievable on a given site, and dual occupancy regulations in Victoria vary by municipality in ways that are not always obvious when reading a planning scheme yourself.

Before any design work begins, we assess your site against the relevant planning requirements for your local council. That assessment tells you clearly whether a dual occupancy or townhouse development is achievable, what the realistic yield looks like, and what conditions any permit approval is likely to carry. Getting that picture accurately from the beginning is worth considerably more than months of planning built on assumptions.

Frame for duplex development under construction

Two homes, one well-considered design

A duplex puts two separate dwellings on a single title, and when the floor plan is designed well, neither one feels like the compromise half of the arrangement. RD Building Design approaches duplex floor plans with both occupants in mind, working out how the two dwellings relate to each other on the site, and how each one connects to outdoor space.

Floor plan — 3 bedroom + studio, 6m wide lot

Built faster, built better

RD Building Design specialises in designing homes using Structural Insulated Panels. The construction process takes roughly half the time of a conventional build. Homes stay warmer in winter and cooler in summer. The whole method produces far less material waste on site than traditional framing. It is a smarter way to build.

New duplex house design

Why use a building designer for your development

Homeowners and investors searching for duplex builders often encounter companies whose primary interest is construction. A building designer's focus is different. We produce the duplex plans and townhouse floor plans, manage the permit documentation, navigate the planning scheme, and deliver complete plans your builder picks up on day one.

Our drafting services run from site briefing and feasibility through to full construction documentation and council submission. We understand what planning officers in your local council want to see in a multi-unit application, and if a development reaches VCAT, our documentation is prepared to a standard that holds up to scrutiny.

Narrow lots and western suburbs sites

Melbourne's western suburbs development sites typically present with frontages of ten to fifteen metres, shared side boundaries, and neighbours whose amenity any multi-unit application must address directly. These are not complications. They are the parameters good duplex and townhouse design works within.

A two or three storey townhouse on a narrow lot, designed well, delivers generous internal volumes and private outdoor space for each dwelling. Picture both dwellings oriented to capture northern light, each with its own entry and its own sense of address on the street. That outcome comes from design work that starts with the site and builds outward from there, not from a standard duplex floor plan adapted to fit.

Subdivision, permits, and the approval path

A dual occupancy development follows a simpler planning pathway than a townhouse or multi-dwelling project, which makes it a manageable starting point for homeowners developing their land without taking on the complexity of a larger scheme. For townhouse developments, strata or community title subdivision involves coordinating the planning permit and the subdivision plan as two related but distinct processes, and the sequencing of those processes affects the project timeline more than most developers expect.

We coordinate both, so the two processes move in step rather than one waiting on the other.

What does a duplex or townhouse development cost

Duplex costs and townhouse development costs in Melbourne vary with site size, design complexity, construction specification, and what council conditions end up requiring. Our duplex plans and townhouse floor plans give builders a complete picture of the project, which produces accurate quotes and fewer surprises when construction begins.

Subdivision costs, including surveying and the title process, are a separate line and we will point you to the right professionals for those. What we give you early in the conversation is a clear, realistic picture of what the design and permit phase involves.

Contact RD Building Design about your new home

Start with a feasibility conversation

For investors and property owners assessing a site, the most useful first step is a proper site assessment: reviewing your block against the relevant planning scheme, identifying what yield is genuinely achievable, and mapping the permit conditions a multi-unit application on that site is likely to attract. Bring us your address and your questions.