“There needs to be a strategic rethinking of how we design buildings in order to maximize the value of the materials and embodied energy contained within them. New buildings must be designed with durability, adaptability, and disassembly in mind.”
-Â from Chapter 7, ‘Constructive Environmentalism’
Author: Jim Taggart – Abacus Editions (2011)
With the current discussions about the Kyoto Protocol and climate change on the rise, Jim Taggart’s new book Toward a Culture of Wood Architecture comes at the turning of the tide. As an urgent and critical document on how increased wood use could mitigate climate change, this thorough and thought-provoking book could not have arrived a moment too soon.
Chocked full of poignant observations on the use of wood as a building material throughout history along with supporting case studies, documented through stunning photography and lively graphics, the book is also a monograph of some of Canada’s most formidable architects and structural engineers who have explored the potential of wood as both a traditional material that is a part of Canada’s identity and a modern innovative medium rivaling its concrete and steel counterparts.
Indeed, in the book’s introduction, both Taggart and Michael Green together imagine a future in which 30-storey wood structures populate our city skylines. With BC having increased the allowable built height of wood buildings to six-storeys in 2009, and the recent opening of a nine-storey wood tower in London, England, Taggart and Green’s vision may not seem so far-fetched.
So how can this be possible?
The simple answer: new Computer Numerically Controlled (CNC) technology and engineered wood products (EWP’s) have enabled the possibility of wood structures that can withstand fire and perform structurally much like concrete and steel, all without the negative side effects of the embodied energy in those materials. With the current demand to discourage urban sprawl and reduce each building’s carbon footprint, wood replacing concrete and steel in our residential towers could respond directly to some these concerns.
The book wisely begins by looking at early wood use within two cultures that have used the material for millenia and whose cultural identity is inseparable from the substance – Norway and Japan. Carrying his keen observations forward, Taggart explores the wood structures of Canada’s First Nations and highlighting how wonderful buildings as those at the UNESCO World Heritage Site in S’Gang Gwaay have been allowed to return to the elements naturally in the tradition of Haida culture that built them.
The remainder of the chapter looks at the structures created by the first settlers that adapted European styles of construction into wood. Only a few existing examples having survived the ravages of time and fire while others have had to be reconstructed (such as Nova Scotia’s Port Royal Habitation). However, it is wood-built in engineering structures – such as covered bridges and trestle bridges – that Taggart believes are most representative of Canada’s early wood culture, along with the majestic grain elevators that populate the Canadian prairies.
As Taggart laments at the end of the chapter, wood use and wood innovation dramatically declined in North America with modernism and its preference for steel and concrete. While two years following the second world war saw 1.5 million wood homes built in the US alone, this led to the material being seen quantitatively rather than qualitatively. The result was that while Europe pressed forward innovating and using engineered wood products – such as glulam, Parallel Strand Lumber (PSL), and Cross Laminated Timber (CLT) products – North America and Canada were left behind. Only now with the recent push by life-cycle costing and sustainable forest management has wood use again begun to enter our collective psyches.
While in the 1970’s irresponsible forestry management, like clear-cutting, turned the public perception against wood use, fire safety has driven the argument against its use. With several major European and North American cities burning to the ground at the turn of the last century, the arrival of fire resistant concrete and steel led to their predominant use in the twentieth century. National and local building codes have consequently been slow to recognize the use of wood in commercial, municipal and cultural buildings. As Taggart demonstrates in several built case studies, more recent innovative wood use across the nation has shown wood can achieve structural superiority and boast less embodied energy. He states:
“There are many reasons to revive a wood building culture in Canada: to reaffirm cultural identity, to re-establish regional character, to resuscitate local economies, and perhaps more importantly, to make a contribution toward the mitigation of climate change.”
While up until the 1950’s the extent of Canada’s use of engineered wood products was limited to the glulam beams in local supermarkets and ice rinks, the federal government has nevertheless been doing wood research in laboratories in Quebec and British Columbia since 1913. Of particular importance was the establishment of the Canadian Wood Development Council in 1959 – later renamed the Canada Wood Council (CWC) in 1964 – who is responsible for testing and certifying wood products and their use in Canada.
Taggart continues, pointing out how the implementation of the National Building Code in 1941 – established to safeguard structures against fire and seismic activity – and their regulations regarding wood combustibility relegated the material to small structures between one and three storeys for decades. Not until 1990 were building codes amended such that wood structures with sprinklers could be built up to four storeys – with BC going one step further, as already noted, allowing for wood structures to now reach six storeys. As a result, a number of innovative and striking wood buildings have since been built in BC, especially in the run up to the 2010 Winter Olympics.
Next is a brief history of the development of various engineered wood products, including plywood (the first EWP to be patented in 1860) as well as the development of parallel strand lumber (PSL) and cross-laminated timbers (CLT). Taggart points out how it wasn’t until the 1980’s – when the environmental movement had forced the forest industry to implement sustainable forest management (SFM) guidelines that research in different engineered wood products took off due to the shift in the business model for responsible forest harvesting.
In one chapter entitled ‘Mitigating Change & Carbon Sequestration’, Taggart speaks to the fact that Canada has the largest commercial forest stewardship of all the developed nations, comprised of some 134 million hectares. Of this area, approximately 30% has been deemed available for commercial wood production, with 0.5% of this being harvested annually. Furthermore, younger trees sequester more carbon than older trees,so logging trees that are at the end of their natural sequestration cycle locks in the carbon that would otherwise be released into the atmosphere. As an example, he notes that one cubic meter of wood has absorbed the equivalent amount of carbon emitted by an automobile driving from Vancouver to Quebec City.
Continuing the discussion of environmental impacts, Taggart introduces the important concept of embodied energy. More specifically, how engineered wood uses 2-3 times less carbon in its manufacture than steel, and 6-12 times less the fossil fuels. To illustrate, he discusses the Eugene Kruger School of Forestry in Laval, Quebec, and how it was used as a case study to compare wood and steel. The wood building’s passive design features alone contributed to a saving of 30% in its operational costs, as well as resulting in a reduction of 40% embodied energy. Towards this end, Taggart also introduces the work of Julius Natterer, and his landmark paper A Way to Sustainable Architecture by New Technologies for Engineered Timber Structures’ (2005) in which he introduced the notion of constructive environmentalism.
The seventh chapter of the book is the most comprehensive, as within it Taggart presents many notable examples of constructive environmentalism through wood use, including the Whistler Public Library by Hughes Condon Marler, Vancouver’s Canada Line Stations by Perkins + Will and VIA Architecture, and the Richmond Oval by Cannon Design. All of these projects demonstrate effective use of wood combined with other sustainable strategies, including rainwater harvesting, and heat recovery. In many instances, the same structural engineer and contractors continue to demonstrate excellence in wood innovation, including Fast + Epp and StructureCraft Builders.
Taggart includes other landmark wood projects, such as the remarkable entry and atrium of the Surrey Central City by Bing Thom as well as Richmond City Hall by Dialog – highlighting how wood constructed municipal buildings would have traditionally been frowned upon. Similarly, he discusses how Frank Gehry’s use of engineered wood in his recent AGO renovation in Toronto has helped to bring wood back to the cultural stage.
The chapter ends with the discussion of wood’s disassembly and reuse for future buildings, citing the remarkable Materials Testing Centre realized by Peter Busby‘s office in 1999, in which 90% of the building was made from two disassembled heavy timber structures.
As an added bonus, the book boasts fantastic construction details in its margins, including the axonometric of the majestic tree columns of the Carlo Fidani Peel Cancer Center in Mississauga, the roof panels of the Richmond Oval, the universal connector used in the Squamish Adventure Center, as well as cross sections of the curving columns in the West Vancouver Aquatic Centre.
At 144 pages and populated with stunning photography, Taggart – the editor of the excellent SAB magazine – has given us an eloquent argument for the increased use of wood in our built environment. Toward a Culture of Wood Architecture is a tour de force exposition on how wood use can mitigate climate change like no other building material, being as it is both a renewable and plentiful resource.
By becoming responsible stewards for our forests, wood can become the material of the future, remaking our cities in ways we cannot yet imagine. And as Michael Green of mgb eloquently sees it, there is no question of what needs to happen:
“Each time we choose to build in wood we are part of a critically important chain of responsibility that will see the elegance of the living tree through to a new life in a building.”
For information on how to get a copy of the book, contact firstname.lastname@example.org.
Sean Ruthen is a Vancouver-based architect and writer.