Coogee House III
Architect: Tribe Studio Architects
Builder: P+S Design and Construction
Location: Coogee, NSW
At Coogee House III, the structural design acts as a quiet backbone for a bold architectural vision. Working with Tribe Studio Architects and P&S Design and Construction, Partridge focused on balancing heavy, traditional masonry with the precision engineering needed for a modern home. The standout feature is a stepped brick arched tunnel – a structure that looks like a simple, continuous masonry form but actually relies on a clever, hidden skeleton to stay standing.
To create this look, the tunnel uses steel beams at the base and ends to handle the outward pressure, while custom-cut plates follow the stepped brickwork to provide invisible support. Because the arches are staggered, standard tying methods wouldn’t work; instead, a reinforced layer of screed was added over the top to bind everything together, allowing the tunnel to behave as a single unit. With spans reaching up to 7.5 metres over large windows, the engineering had to be incredibly stiff to ensure the heavy brickwork didn’t move and damage the glass below.
This use of brick carries through underneath the balconies, where it forms the ceilings. To make this possible, the timber-framed floors were engineered to stay exceptionally level under the weight. By using specialist systems to hang the bricks from the timber, the team ensured the floors were rigid enough to prevent the mortar from cracking over time.
The site also presented challenges below ground, where loose sandy soils required a careful approach to the garage excavation. The team used a “top-down” method, casting the ground floor slab first to act as a brace for the shoring walls. This allowed the soil to be removed safely underneath while keeping the surrounding ground stable. Higher up, the home’s shape is defined by a series of welded steel frames. A large primary frame sets the roofline, while smaller frames sit inside it to create the repeated angled ceilings seen throughout the rooms.
The perforated mesh stair also became a major focus during construction. Working closely with the builder and architect, we refined the landing supports and explored different ways to stiffen the treads to balance structural needs with the practicalities of fabrication. By using finite element analysis on the mesh itself, we were able to slim down the design, achieving the sense of lightness and porosity the architect envisioned without compromising strength.
Ultimately, the success of the project came down to coordination and restraint. By hiding complex steel supports within the masonry and carefully planning the build sequence, the structural engineering stayed out of sight, allowing the architecture to take centre stage.
