Background
MHN Design Union Pty Ltd appealed a deemed refusal of its application to modify a 2023 development consent for a new dwelling and pool at 8–12 Balmoral Avenue, Mosman. The proposed modification added an 18-square-metre rooftop terrace and an external access staircase.
The Council opposed the modification on view-loss and privacy grounds. Nearby owners, including owners in Redan Street, objected to the terrace’s bulk, loss of views and overlooking. The parties agreed the modified proposal remained substantially the same development as the original consent; the dispute concerned its amenity impacts.
The Court’s Holding
Commissioner Horton dismissed the appeal and refused the modification application. The Court found that view loss from the amended proposal was minor: affected neighbours would retain water and Balmoral views, and some lost views were obtained through acute diagonal sightlines.
However, the external stair created unreasonable visual-privacy impacts, particularly for 21A Redan Street. Its elevated, projecting return-stair configuration enabled direct and sustained overlooking of neighbouring living areas, bedrooms and private open space. The limited landscaping did not adequately mitigate that impact.
The stair therefore failed the Mosman Residential Development Control Plan controls requiring screening where outdoor spaces directly overlook neighbours and permitting rooftop terraces only where privacy and view impacts are absent. Although likely terrace noise was no more intrusive than ordinary residential balcony, terrace or backyard use, that did not cure the visual-privacy harm.
Key Takeaways
- A rooftop-terrace modification may be substantially the same development yet still be refused on its planning merits.
- Minor view loss did not justify refusal here, but direct overlooking from the access stair did.
- Landscaping and separation distances did not adequately address a sustained, elevated sightline into neighbouring private areas.
Why It Matters
The decision distinguishes between the rooftop terrace itself and the practical effects of how it is accessed. In sensitive residential settings, an external stair can be the decisive source of privacy harm even where the terrace is small and view loss is limited.