AJC Architects' Weathering-Steel Lookout Opens in Sydney's Hornsby Quarry

AJC Architects has completed the Southern Lookout, a 42-meter weathering-steel walkway and platform suspended over the former Hornsby Quarry in Sydney, Australia. The structure is the first architectural phase of a 60-hectare landscape-led masterplan for Hornsby Park, a site that was inaccessible for over a century. The lookout is engineered to minimize ground disturbance, anchored by four angled columns converging on a single central footing, allowing an 18-meter span and a six-meter cantilever. A grated steel floor permits light and rain to reach the vegetation below, while providing hikers with a sensory experience of height. The design adopts an industrial vernacular referencing the quarry's operational history, using weathering steel that develops a patina to blend with the bushland. The project aims to reconnect the public with the site's industrial past and ecological future, framing views of the volcanic diatreme and emerging water body. The lookout is part of the transformation of Hornsby Park into a regional recreational hub.