The forestry sector is touting a new technology that it claims could revolutionize the construction industry.
Cross-laminated timber (CLT) looks exactly as it sounds: pieces of lumber stacked in different directions and glued together to create a strong and airtight building material.
Unlike traditional products such as glued-laminated timber, CLT’s strength is derived the way its lumber is layered, which is similar to the wooden block game, Jenga.
Vancouver architect Michael Katz built North America’s first CLT display home during the 2010 Winter Games.
“I’m going to go out on a limb here and say what I believe: I think CLT is the single most important building product ever,” Katz said.
Katz, a former chief planner for Grosvenor International, the development arm of the Duke of Westminster, believes CLT could replace concrete.
“Concrete is responsible for 6% to 8% of the world’s carbon emissions,” he said. “The beauty about CLT is it’s a renewable resource; most other building products are non-renewable resources.”
The architect used CLT panels to build his L41 home, an ultra-compact (220 square feet) studio apartment at the Centre for Digital Media campus on Great Northern Way.
Katz used CLT not only because it’s an environmentally friendly product, but also because it’s easy to assemble and nearly soundproof.
That means it’s perfect for laneway and student housing, Katz said, adding that he hopes to mass-produce and one day sell the L41 for less than $60,000 each.
But aside from miniature houses, how could wooden blocks hope to compete with the concrete industry?
Mary Tracey, executive director of Wood WORKS! BC, said CLT is already competing with concrete in Europe.
“They’re way ahead of us,” Tracey said.
With 15 main CLT production sites between them, Austria, Germany and Switzerland are at the head of the pack.
London is home to a nine-storey CLT building (the first floor is concrete); other European nations have built four- and five-storey buildings with CLT. B.C., on the other hand, is just getting started.
FP Innovations, the world’s largest non-profit forest research institute, only recently released a handbook about CLT, and the technology has yet to be incorporated into the B.C. building code.
So far, there are only two companies out west that manufacture CLT: Structurlam Products in Penticton and CST Innovations in New Westminster.
Mark Zaturecky, CST’s business development manager, said CLT is still in its infancy in North America, but there’s a growing list of architects and engineers who are asking about it.
“It’s going to be a huge market,” Zaturecky said. “It’s going to take a lot of time to get there, 10 or 15 years, but … things are going to start growing.”
The company supplied CLT panels for Katz’s L41 home and is manufacturing panels for the University of British Columbia’s $27 million bioenergy research and demonstration project.
The province’s Wood First Act is also creating interest for the technology.
The act requires wood to be considered as the primary building material in all new provincially funded buildings.
That means there’ll likely be more wood in commercial non-residential projects where concrete has traditionally been used.
As well, the building code was updated in 2009 to increase the maximum height for wood-frame residential construction to six storeys from four.
The changes will create more opportunities for CLT, but not everyone is embracing the wood revolution.
The BC Ready-Mixed Concrete Association has criticized the Wood First policy for supporting forestry at the expense of the concrete sector, and the organization remains skeptical about CLT.
“It’s touted by the forest industry as the next structurally superior product, but we want to see some more proof,” said Carolyn Campbell, the association’s executive director.
She also questioned CLT’s ability to withstand damage from fire and earthquakes, though proponents argue that it’s somewhat fire resistant due to its thickness and has been shake-tested for seismic events.
Evidence comparing CLT’s performance to concrete’s remains elusive.
Russell Acton, principal of Acton Ostry Architects, frequently uses wood in his designs.
Although he’s interested in CLT, he believes it would be hard pressed to break into the traditional residential construction sector.
“People like to extol the virtues of cross-laminated timber and how it’s been used in Europe for house building for decades … but then we also have to remember that stick-frame technology … offers many, many benefits in terms of its economic utilization of wood,” Acton said.
Still, Katz is adamant that CLT could take wood to new heights, perhaps 12 storeys or higher.
But as enthusiastic as he is, Katz also recognizes that it won’t happen right away.
“There’s something about humans that resists innovation,” Katz said. “It takes time.”