By Rick Reynolds
“Urban Timber: From Seed to City,” a new exhibit at the Boston Society of Architects’ Gallery Space, celebrates wood as a natural and sensible building material for cities, while highlighting wood’s adaptability, versatility and extraordinary technical qualities. It also highlights some innovative thinking going on at Bensonwood.
Included on display at the BSA Space — and the result of an open competition — are four winning projects proposed by emerging architects featuring innovative structural uses of timber.
The winners collaborated with mentor architects, engineers and material suppliers to develop and realize their installations in the gallery. Each piece in the exhibit is an art project — and would look right at home in any modern art gallery — but is trying to prove a design theory.
Two of the four design installations in the exhibition involve Bensonwood associates. The first, “Four Corners” by Yasmin Vobis and Aaron Forrest, enlisted Bensonwood chief structural engineer Chris Carbone as a mentor. The Four Corners installation turns the traditional timber framed New England barn inside out using cross-laminated timber.
The second, Bensonwood Designer Tim Olson’s dynamic “Coopered Column,” weighs about 3,000 pounds and consists of 118 timber pieces and over 250 screws. Titled “coopered” because it borrows from the design of a barrel; the interlocking timbers act like staves, and a belt of screws holding it together mimic the metal hoop of a barrel or other wooden vessel made by craftsmen known as coopers.
Olson’s bowl-like installation is called a column because a cylindrical support was his original design, a wooden structure that could handle the weight of a skyscraper. He flattened the column into a bowl shape to demonstrate how the design could handle stresses necessary to support a building. You can listen to a recent NHPR story on Tim’s installation.
The exhibit also explores how using wood in mid-rise buildings can combat climate change and underscores wood’s potential as the need for high-performance, low environmental impact structures continues to increase in our urban centers.
In addition to exploring wood technology and recent innovations in the array of engineered timber available to architects and engineers, the Urban Timber exhibit dispels common myths associated with building in timber, such as the notion that heavy timber is not sufficiently fire resistant. In some instances, engineered wood retains its integrity even better than steel. Cross Laminated Timber (CLT), for example, has a higher resistance to fire because of its thickness since the outer layers, when charred, protect the inner layers, just as a large-diameter tree does in a forest fire.
While the perception of wood in America as a lesser building material endures, Yugon Kim, founding owner/partner of IKD and co-curator of the BSA exhibit, believes that Urban Timber: From Seed to City will show that the use of timber as the primary structure in mid-rise building construction in Europe proves there is a new future for wood buildings.
Urban use of heavy timber has long been an interest here at Bensonwood. In 2007, Bensonwood and Unity Homes founder Tedd Benson was a leader of the UMass Amherst Wood Structures Symposium that explored technological advances in green buildings, as well as digital fabrication with wood and engineered wood products. Organized by the university’s Building Materials and Wood Technology program, the event highlighted new advances in contemporary wood architecture and presaged the current interest in building high-rises with wood. Currently, the tallest wooden buildings are only around 100 feet tall, but constructing much taller timber buildings is now a realistic idea.
In recent years, the technical advances that Bensonwood and Unity Homes have helped develop have given rise to a broad range of process innovations, such as CNC milling and off-site assembly, as well as engineered-wood products with superior performance qualities, such as the glulams (glued, laminated timber) and CLTs used in nearly all of our projects for their strength, flexibility and reliability.
Thanks to novel composites and engineered wood products, such as glulam beams and CLTs, several multistory buildings have already been erected around the world with timber skeletons, and plans for taller buildings are in the works.
Urban timber proponents have been making a larger argument to the building industry and to policy makers that to build cities with a lower environmental impact, wood is not just promising but necessary. It’s a plentiful resource that grows back relatively quickly, and even pulls carbon out of the atmosphere during its life cycle.
Architect Michael Green, a passionate advocate for building wood high-rises,said in a recent TED Talk, “Steel represents about three percent of man’s greenhouse emissions, and concrete is over five percent.” He estimates that every 20-story building made out of wood instead of steel or concrete saves around 4,300 tons of carbon, equal to around 900 cars removed from the road in a year.
There are still some major environmental issues to tackle, of course, such as how greatly increased timber harvesting would affect our ecosystem. However, the USDA recently announced a major initiative to promote innovative, sustainable wood building materials for environmental protection and job creation.
The exhibition was curated and designed by Yugon Kim and Tomomi Itakura, principals of the Boston-based architecture firm IKD.
The Urban Timber show will remain on display in the BSA Space at 290 Congress Street in Boston through September 30. Admission is free and open to the public. The public program includes a series of collaborative public workshops and lectures to provide extra platforms for dialogue and knowledge-sharing between key players in the industry. For more information on the Urban Timber exhibit, visit the BSA website.