Brisbane City Council has approved a portable residential building forming part of an existing dwelling house in Oxley, using a QDC performance solution to address a corner lot’s setback constraints.

The proposal involved adding a 36 m² portable building to a 640 m² corner lot in the Low density residential zone. Rather than meeting the Queensland Development Code’s acceptable solutions outright, the application relied on a performance-based assessment, demonstrating the proposal still achieves the underlying design and siting outcomes the code is intended to protect.

Corner lots come with setback requirements on more than one frontage, which can limit where a new structure can sit relative to both street boundaries. In this case, the proposed building sat just 690 mm off the Kingsgate Street boundary, against an acceptable solution of 6,000 mm, with a corner truncation encroachment of 3.3 m in height against a 2 m acceptable outcome.

Council assessed the proposal against the relevant performance criteria of QDC MP1.2 and confirmed compliance, approving the application subject to the development being built and sited in accordance with the approved plans. This gives the owners additional residential space while retaining the existing home.

Secondary Dwelling’s are not automatically exempt from planning approval, and corner lots add an extra layer of complexity through dual road setbacks. Where a proposal doesn’t meet the acceptable solutions, a QDC performance solution can still achieve approval, but it requires a well-supported planning case, not just a design.