Entrant:
Andrew Irving / Irving Smith Architects
Category:
9. Hybrid building award
Photographed by:
Patrick Reynolds
Overview
Wall-É
Wall-É occupies a small central city site, surrounded on all sides by low level commercial development. Wall-É occupies the full site, where unlimited site coverage is permitted.
The typical response to a narrow central site, is to install full height concrete fire walls to each of the long boundaries.
Wall-É breaks down the ‘box’ of this typical response, using lighter timber construction, and manipulation of Fire Code requirements, to allow a highly glazed mid-section recessed from the boundary. The upper floor takes a similar approach, allowing natural light and ventilation on all sides to both upper levels.
Ground level construction is Precast Concrete, to enable this extent of site coverage. The central concrete circulation core extends vertically and acts to brace upper levels. Selective use and location of concrete allows a simple foundation solution, meets the requirements of the fire code, and acts as a firm base for the lighter weight and more open levels above.
Above, an expressed structural LVL frame and lightweight Potius flooring system form the recessed mid-level. To the upper level, more conventional lightweight construction, supplemented with Engineered timber allows a light weight, fire rated solution to the upper floor.
The use of structural timber allows a lighter weight response, and subsequent reduction in bracing elements. The side walls in particular are manipulated and shaped, allowing glazing, ventilation, and shade elements to be woven together.
A raised floor system is used to acoustically isolate the lightweight upper floor system, and to reticulate services throughout the open plan upper floor fitout.
On each upper level, but particularly the mid floor, LVL post, beam and POTIUS floor elements are fully expressed, along with simple steel bracing, and the exposed precast of the circulation core and low-level perimeter walls. Applied finishes are reduced in favour expressing the bones of the building. The Timber and Concrete hybrid construction approach is expressed as integral to the architecture.
This approach has allowed prefabrication, reduced construction time, and an economic build cost, in the order of $3,000.00 per square metre.
Our constructional approach yields a ratio of occupation:
1.5 – levels of traditional concrete
0.5 - level of glazed, recessed veranda
1.0 – level of lightweight upper floor.
This ratio enables access to natural ventilation and daylighting on upper floors, minimising need for mechanically assisted systems.
Particularly on the mid-level, natural light, and ventilation, in concert with thermally massive concrete floors and shear walls and expressed timber members, moderate temperature and acoustics in an open and highly passive response to provision of inner-city workspace.
The perimeter veranda sustains a small green space in the city, moderating light and view; we work on a veranda, effectively outdoors.
We have assessed this design with a more typical occupation of this site, as described above, using the Naylor Love Carbon Comparison Calculator. This calculation suggests a reduction in embodied carbon at completion of construction in the order of 60-70,000 kg CO2 eq, approximately 80 kg CO2 eq/m2.