A precise architectural intervention in the bushland landscape surrounding a former rock quarry
Located on Sydney’s northern edge, the Southern Lookout is a 42-metre-long elevated viewing platform in Hornsby, designed by AJC Architects.
Previously closed to the public for more than a century, the site is now being transformed through a landscape-led masterplan into a 60-hectare regional open space. The lookout forms the first architectural intervention within this transformation, establishing a new way for visitors to engage with the site’s natural and industrial history.
Drawing directly from the quarry’s legacy, the architectural response references the character and scale of the former quarry and its exposed rock walls. The lookout is realised as a weathering steel platform, expressed as a simple and robust form that appears as though it may have formed part of the original quarry operation.
The experience of the lookout unfolds as a choreographed sequence. Visitors move beneath, within, and beyond the forest canopy, with views initially contained to emphasise the surrounding landscape.
A grated steel floor provides a subtle awareness of the falling topography below, while visual focus remains directed forward. At the end of the platform, the full quarry void is revealed, framing the volcanic diatreme and water body.
Structurally, the lookout is conceived to maximise projection into the quarry while minimising structural steelwork and ground disturbance. The platform is anchored into the embankment and balanced on four angled columns supported by a single central footing, achieving an 18-metre span and a six-metre cantilever towards the quarry.
The Southern Lookout resolves as a restrained architectural intervention—industrial in character yet settled within the bushland landscape.
Hornsby Park, the former quarry is being reimagined by Hornsby Shire Council as a regional open space.
