Building planning for dual occupancy: what councils look for

Dual occupancy projects are often seen as straightforward. Two dwellings on one lot, usually low-rise, often in established residential areas. On paper, they appear to be low-risk. In practice, they are one of the most common application types to stall due to small but critical planning issues.

If you have worked in building planning or site planning for any length of time, you have probably seen it. A proposal that should be compliant gets delayed because a setback is misread, an overlay is overlooked, or the Statement of Environmental Effects does not clearly address the controls council actually cares about.

This article breaks down what councils typically look for when assessing dual occupancy applications, and why getting clarity early can save weeks or months later.

Zoning and permissibility come first

Before anything else, councils check whether a dual occupancy is permissible on the site. This sounds obvious, but zoning interpretation is one of the most common sources of delay.

Some zones allow dual occupancy outright. Others allow it with consent. Some prohibit it entirely or restrict it based on minimum lot size or frontage requirements.

What councils want to see is a clear and accurate interpretation of the Local Environmental Plan that confirms permissibility and explains why the proposal fits within that zone. Vague statements or copied wording often trigger requests for clarification.

Good building planning starts by locking this in early so the design team is not working off assumptions.

Minimum lot size and density controls

Once permissibility is established, councils move straight to density controls. This usually includes minimum lot size per dwelling, floor space ratio, site coverage and landscaped area requirements.

Dual occupancies often fail here, not because they exceed a control by a large margin, but because the calculation method is unclear or inconsistent with council practice.

Councils want to see calculations that are transparent and easy to verify. If an officer has to guess how a number was derived, they will come back with questions.

Clear site planning diagrams and well-explained calculations reduce assessment time significantly.

Setbacks, height and building envelope

Most dual occupancy applications sit in established neighbourhoods, which means context matters.

Councils assess front, side and rear setbacks carefully to ensure the development fits the existing streetscape. Height is not just measured in metres but also in relation to adjoining properties and slope.

From a planning perspective, councils are looking for a proposal that respects the intended building envelope rather than pushing every control to its limit.

This does not mean variations are impossible. It means any variation needs to be intentional, justified, and clearly linked to the planning objectives.

Parking, access and waste

These are the issues that seem minor but cause disproportionate delays.

Parking numbers must meet the Development Control Plan requirements. Access must be safe and functional. Waste storage and collection points must be realistic.

Councils often refuse or delay dual occupancy applications because driveways are too steep, bins cannot be serviced, or parking spaces do not meet minimum dimensions.

Addressing these upfront in the planning documentation avoids unnecessary back and forth later.

Overlays and site constraints

Flood, bushfire, heritage, contamination and biodiversity constraints frequently apply to sites that otherwise look simple.

Councils expect applicants to identify relevant overlays early and explain how they affect the proposal. Ignoring them does not make them go away. It usually just delays the assessment.

From a site planning perspective, this is where many low-risk projects become high-friction projects simply because the constraints were not identified early enough.

Why early planning checks matter for dual occupancy

Dual occupancy projects are rarely controversial. They are also rarely forgiven for being incomplete.

Councils assess a high volume of these applications, which means poorly prepared documentation is often pushed to the bottom of the queue.

This is where early building planning and site planning checks make a measurable difference. Identifying the correct approval pathway, confirming controls, and flagging risks before lodgement prevents avoidable delays.

How Planna helps with low-risk projects

Planna is particularly effective for low-risk projects like dual occupancies because it focuses on clarity and speed without cutting corners.

Instead of waiting weeks for preliminary advice, Planna provides fast planning checks that confirm zoning, permissibility, controls and site constraints early in the process. This allows designers and builders to move forward with confidence rather than assumptions.

Planning reports are structured around how councils actually assess applications. Controls are clearly cited. Calculations are transparent. Risks are flagged upfront.

For many dual occupancy projects, this means fewer council questions, faster assessments, and lower planning costs compared to traditional consultant pathways.

It is not about replacing planners. It is about removing unnecessary friction from straightforward projects so time and effort can be spent where it actually adds value.

A practical approach to better outcomes

From a town planning perspective, the goal is simple. Help councils assess applications efficiently by giving them what they need the first time.

For dual occupancy developments, that means clear building planning, thoughtful site planning, and documentation that directly addresses the planning permit requirements.

Tools like Planna support that outcome by making early checks faster, more affordable, and more consistent. For low-risk projects, that can be the difference between a smooth approval and months of avoidable delay.

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