About the project
Located on the edge of central Sydney, Prince Alfred Park is a place for lunchtime workers to relax, as well as a recreational park for local residents. It includes a pool, which was upgraded by Neeson Murcutt Architects in conjunction with Sue Barnsley Design.
Modifying the existing shell of the building, the design team added a new ‘services and pool facilities’ building, a pool concourse as well as more landscape. However, they wanted the new building to be as discrete as possible.
In response, they came up with a ‘folded landscape’ strategy, whereby meadows of native grass in the park have been ‘folded over’ the pool facilities to create a rolling park landscape.
“The green roof was a direct result of an urban strategy about the park. Folding a park over the building enabled us to minimise the impact the building had on the park,” said Rachel Neeson of Neeson Murcutt Architects.
“It also meant that you don’t see Chalmers Street from the pool space itself – you don’t see the traffic, or hear the buses. The pool space becomes other-worldly.”
Why it works
With landscape premiated over built form, the design of the 2,320sqm green roof – the largest of its kind in Sydney – has evolved beyond a meadow camouflage; topped with 35, 917 plants, it is also important in the context of the park’s other landscape elements, ensuring continuity between the spaces and encouraging movement.
Landscape architect Sue Barnsley adds that the team was interested in bringing an ecological sensibility to the new park that recognised new maintenance practices. “Limiting mowing, discouraging access and creating habitat have allowed the ‘urban meadows’ to add colour and texture to the parklands,” she says.
“The distinction in ground surface between meadow roof and grassy mounds add to the playful expression of the pool architecture and its detail resolution.”
The stabilising and drainage materials were carefully chosen by project engineers, Acor, who, with the architects, selected the waterproofing products. BASF Conipur M865 Thix membrane, and BASF Sonoguard Top Coat, a moisture-cure polyurethane waterproofing membrane system, have been used.
Bentofix waterproof membrane, and Bentonite water proofing mass were also utilised to achieve long term protection against water ingress.
Tensar geogrid SS30/30 + SS20/20 was used as the soil stabilisation layer, and the geofabric was Bidum H34 and A384.
Although the greatest design challenge for the team was making the 1,000m2 pool building disappear in the park landscape, the precise alignment of the folding perimeter fence across a sloping ground line also proved a challenge. Stainless steel mesh for fencing from Ronstan has been used for the fencing, which winds like a ribbon in the landscape, up through the meadow and over the green roof.
Bringing nature to the city, the green roof at Prince Alfred Park successfully conceals the presence of the building from Chalmers Street, whilst creating an urban habitat, and amplifying the pastoral quality of the landscape. On a larger scale, the landscaped roof gives back to the city.
“[It] is continually transpiring, oxygenating its surrounds, cooling and humidifying the site, and sequestering carbon,” Barnsley says.
Neeson Murcutt Architects and Sue Barnsley Design (8297 3530).