Image credit Johnston Architects
What's not to love about wood? It sucks in carbon dioxide and when you put it in buildings, sequesters the carbon for years. It's a renewable resource when properly managed and harvested. It is often local. But it has not been commonly used as the exterior of larger buildings; it is combustible and it is not low maintenance.
So it was interesting to see two projects show up on Arch Daily in as many days that are clad in wood in such similar fashions, continents apart. Above: a lovely mulitfamily project in Seattle by Johnston Architects.
The Footprint at the Bridge Project is a multifamily townhouse project that encourages daylighting, natural ventilation, rainwater collection (lots of that in Seattle), and healthy materials. It is seeking LEED Platinum. It is built with locally sourced FSC certified framing lumber and clad in a wood rain screen envelope.
Image credit Edmund Sumner
In Bristol, England, the Badminton Girls School residence is clad in wood, much like the Footprint. Both also have exterior sun control sticking out over the windows. Here the structure is steel and the wood, untreated larch, is used as cladding only. However there are other green features. The architects, Mitchell Taylor Workshop, tell Archdaily:
The building is a high performing design with sustainability at the core of the client brief. The envelope is a super-insulated steel stud frame with lightweight partitions and thermally massive floors. The spaces are naturally ventilated throughout and designed for natural light to all spaces. What heating the building needs is provided by a Combined Heat and Power plant unit that also produces electricity to be used for the building and the wider School.
Badminton School, detail. image credit Edmund Sumner
I'm referring to the emerging use of wooden structures for larger and taller buildings, which is gaining momentum worldwide, especially in Austria and Sweden, but also in western North America. Washington State has started permitting some taller wooden buildings; and recent changes to the building code in British Columbia have increased the permissible height of "combustible construction" for residential buildings, from four- to six-storeys.
The initial driver of this push for regulatory change has been a steadily increasing concern over the environmental sustainability of concrete and steel buildings. Energy-hogging processes used in both the extraction of minerals needed for, and the production of, concrete and steel release vast amounts of carbon into the atmosphere.
On the other hand, the cultivation and use of sustainable-harvest trees, for construction lumber, actually creates a net carbon sink, even when milling, transportation, and erection requirements are factored in. Recognition of this critical difference is increasingly being reflected in widely used sustainability ratings systems.
The Badminton School uses wood as a decorative cladding; the Footprint demonstrates the use of it throughout the entire project. But both represent a trend- the return of wood.
More Wood Architecture
World's Tallest Wood Tower Proposed for Austria
Waugh Thistleton's Timber Tower
Wood Construction Goes Seriously Vertical. But Does it Really Sequester Carbon?
Forest Research Center is Built, Logically, of Wood
School Built From Wood By Sheppard Robson