What’s behind that copper screen? Goddard Building Rooftop Expansion by Conrad Gargett

What’s behind that copper screen? Goddard Building Rooftop Expansion by Conrad Gargett

Challenges included a strict conservation plan, a builder bankruptcy and what seems like a conflicting brief—blend a new cutting edge university facility with a 1960’s monolithic sandstone structure.

The Goddard Building Rooftop Expansion project by Conrad Gargett provides a further habitable level above an existing State Heritage listed building in the heart of the University of Queensland’s St Lucia Campus.

Challenges for the architects included a strict building conservation plan, a mid-project builder bankruptcy and what seems like a conflicting brief—blend a new cutting edge university facility with a 1960’s monolithic sandstone structure.

The result is a distinct but referential addition to the existing building, one that remains what project architect Luke Pendergast calls “quiet” in nature.

“We proposed a contemporary extension, but it was intended to be as quiet as possible,” he says.

“The large copper screen provided this as it obstructs views outward-in and allows the Uni to put whatever they wanted behind the screen, be it a plant room, open spaces, enclosed spaces. ”

The screen Pendergast talks about is an expansive copper type that spans the 16 metres along the length of the fifth floor addition and was chosen for its ageing quality and to compliment the building’s proportions, fenestrations and curtilage.

The screen was manufactured offsite by Craft Metals in Sydney before being shipped north to be assembled onsite. The perforations and folds in the screen are not random, and Pendergast notes that they serve both referential and pragmatic purposes.

“The folding and perforations, that go back and forth, have a couple of ideas behind them,” says Pendergast.

“The first one being that the folds give the screen rigidity meaning that we could use a lower gauge copper because folding it every 200-300mm means it gave it extra wind loading support.

“The perforations, which were custom designed by us and consist of four patterns, also fold into the nooks which provide a unique shadowing effect back into the building.

“In general the copper was chosen because like the sandstone below that changes colour and texture over time and in different weather patterns, the copper we used will patina and change as well.”

Conrad Gargett was restricted by conservation plans that said the building could not rise 2600mm above the existing building’s parapet.

Pendergast notes that he’d have preferred to use more copper and that it was initially specified to span most of the building, but due to budget restraints they turned to a few other materials.

Craft Metals were called on again to provide the southern façade materials, this time Conrad Gargett chose an Astro Snap Lock Cladding system in 630mm pans that were rolled onsite using a 600mm roller and came in pre-finished Colorbond Windspray.

Beyond the facade, the building provides naturally ventilated work spaces for the building occupants who undertake post-graduate level research for the Centre for Excellence in Environmental Decisions.

Perimeter offices have access to fresh air with over 50 per cent of the external façade able to be opened to natural ventilation. Pendergast notes that occupants spend their days working with the building open, with no lighting and no mechanical cooling.

Pendergast notes that choosing a rigid Kingspan Insulated Panel to line the underside of the roof meant the building exceeded BCA fire and Section J requirements because the boards provided a two hour fire rated lid for the building and also quadrupled the NCC insulation provisions. It also meant that he didn’t have to use purlins in the portal frame as the boards were strong enough to span long distances.
Conrad Gargett chose very shallow LED troffer lighting with 55mm depth and almost no required circulation space