What happens if the existing house does not comply with current planning requirements?
Older houses were often built under different planning rules, so they may have setbacks, site coverage or other features that would not meet today’s requirements.
That does not automatically mean the existing house has to be changed or demolished.
If you want to develop the property further, we would first check whether the existing house was lawfully established and then assess how it affects the new proposal. For example, an existing house may take up a large part of the block, leaving less room to meet current requirements for site coverage, private open space, planting, parking, setbacks or separation.
In some cases, the new development may need to be redesigned—or alterations to the existing house may be required—to achieve an acceptable overall development.
Reference: Planning Act 2023 (A2023-18) – Planning Act 2023
Short Answer
An existing house does not necessarily need to comply with every current planning requirement simply because the rules have changed since it was built.
However, if new development is proposed—such as adding a second dwelling—the existing house and the proposed works need to be considered together to determine whether the overall development can satisfy the current requirements that apply to the proposal.
Detailed Explanation
The key distinction is between an existing lawful development and the new development being proposed. A subsequent change to planning requirements does not, by itself, make an existing lawful building unlawful. ACT Planning confirms the broader principle that development or use that was lawfully authorised can continue notwithstanding subsequent changes to planning controls.
For a new residential proposal, however, the site must be assessed under the current planning framework applicable to that development. For example, where an existing dwelling is retained and another dwelling is proposed, the existing dwelling can materially affect whether the overall proposal achieves requirements relating to site coverage, planting area, private open space, solar access, privacy and other site controls. ACT Planning specifically notes that these requirements can apply across the original block when assessing development involving an existing and additional dwelling.
We would therefore review the existing dwelling's approval status, location, setbacks, footprint and relationship to the proposed development before determining whether it can remain unchanged.
If the existing house itself contains unauthorised work, that is a different issue and may require separate investigation rather than being treated simply as an existing non-compliance with today's standards.
No minimum block size does not remove the need for planning assessment.
Would you like to know what these rules mean for your property?
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