Thoughtful Dual Occupancy Design for Complex Sites
Designing a dual occupancy is rarely straightforward. For many homeowners, it involves navigating planning controls, approval pathways and site constraints long before design decisions can be confidently made.
At Elo Architecture, we work with homeowners considering well-considered dual occupancy projects on complex sites, where long-term outcomes, neighbourhood fit and design quality matter as much as feasibility.
Who this page is for
This page is for homeowners and families who are:
Exploring a dual occupancy option
Unsure whether their site is suitable
Navigating planning controls, zoning or overlays
Concerned about neighbourhood character, privacy and scale
Looking for early architectural guidance before committing
This approach is particularly suited to sites affected by:
Bushfire-prone land
Environmental or vegetation constraints
Slope, access or servicing complexity
Established suburban or semi-rural neighbourhoods
It may not be the right fit if the priority is speed or yield alone, without regard for design quality or long-term value.
Understanding dual occupancy on complex sites
While dual occupancy is sometimes perceived as a simple way to add value, many sites involve layers of complexity that influence what is genuinely achievable.
Factors that commonly affect dual occupancy feasibility include:
Minimum lot sizes, setbacks and building envelopes
Bushfire or environmental overlays
Existing dwelling placement and site access
Infrastructure, services and wastewater considerations
These constraints are not obstacles to design, but they must be understood early, as they shape siting, scale, layout and approval pathways from the outset.
Design quality and neighbourhood fit
A well-designed dual occupancy should feel like a considered architectural response, not an overdevelopment.
Our approach prioritises:
Privacy between dwellings
Thoughtful massing and scale
Landscape as an integral design element
Clear separation of uses and entries
Respect for neighbouring properties and streetscape
These considerations are particularly important for retain-and-build projects, where one dwelling remains occupied and long-term liveability matters.
CDC or DA: which approval pathway applies?
One of the most common questions we hear is whether a dual occupancy can proceed under a Complying Development Certificate (CDC) or requires a Development Application (DA).
While some sites may meet CDC criteria, many dual occupancy projects require a DA, particularly where factors such as bushfire risk, slope, vegetation, neighbourhood sensitivity or planning controls apply.
Understanding the correct approval pathway early is critical, as it directly influences:
Design possibilities
Consultant requirements
Timeframes and cost expectations
Early advice can help avoid design work being undertaken on incorrect assumptions.
Common challenges we see with dual occupancy projects
Some of the most frequent issues arise when decisions are made too late or without sufficient context, including:
Assuming CDC is always the preferred pathway
Commencing design before confirming planning feasibility
Treating the second dwelling as an afterthought
Underestimating site and infrastructure costs
Prioritising floor area over privacy and amenity
Early architectural input helps address these issues before they become costly or restrictive.
Budget, builders and delivery approach
Dual occupancy projects often involve costs beyond construction alone, including site works, services, access upgrades and compliance requirements. Our role is to help clients understand these factors early and design within a realistic overall framework.
We work collaboratively with a range of builders and are equally comfortable engaging with a builder appointed by the client or assisting with recommendations where helpful. Clear documentation and coordination are key to a smooth delivery process.
What happens next
If you are considering extending or building a dual occupancy and would like clarity around your options, the next step is a conversation.
This initial discussion allows us to talk through your home, site, planning context and goals, and to understand whether our approach is the right fit for your project.
There is no obligation. The aim is simply to bring clarity early, so decisions feel informed and the path ahead feels considered rather than overwhelming.
Get in touch via the enquiry form to arrange an initial conversation.
