MASS TIMBER FAQ
WHAT IS MASS TIMBER?
Mass timber is a technological advancement that uses engineered wood products such as Glue Laminated Beams (Glulam), Laminated Veneer Lumber (LVL) and Cross Laminated Timber (CLT). They are fabricated by binding together large panels and beams under pressure using adhesives such as Polyurathane, Phenolic, or Polymer Isocyanate glues. The wood’s grain in each successive layer is stacked in alternating grain orientations for added strength. Mass timber is considered as an alternate to conventional reinforced-steel-concrete construction and is ideal for low-to-medium-rise building structures.
HOW DOES MASS TIMBER’S CARBON FOOTPRINT COMPARE TO THAT OF OTHER BUILDING MATERIALS SUCH AS STEEL AND CONCRETE?
It is estimated that one cubic metre of mass timber sequesters one metric ton of carbon dioxide. By contrast, it is estimated that every tonne of manufactured cement produces about 0.47 tonnes of carbon dioxide. Likewise, 0.6 tonnes of carbon dioxide is produced for every tonne of iron manufactured. By supplanting concrete and steel in mid-rise developments with mass timber products, the carbon footprint of such endeavours can be mitigated.
ARE FIRES AND EARTHQUAKES A THREAT TO MASS TIMBER BUILDINGS?
Mass timber structures meet or exceed existing fire and seismic codes in the jurisdictions in which they are built.
Mass timber structures achieve fire resistance because the timber panels char on the outside to create a layer of insulation that protects the interior from damage. As such, it can withstand intense heat to an extent that surpasses existing fire code regulations.
Mass timber’s light weight lends to its strength in seismic events. At approximately 20% of the weight of comparable concrete buildings, mass timber buildings have smaller foundation sizes, which reduce seismic forces. Mass timber’s significant strength for its weight enables outstanding performance in earthquakes.
IS MASS TIMBER A SUSTAINABLE SOLUTION TO MITIGATE CLIMATE CHANGE?
Yes! While concrete and steel create carbon dioxide in their respective manufacturing processes, mass timber captures and stores carbon dioxide as forests grow. Mass timber is very much a sustainable building material provided that forests are effectively managed and sustainable harvesting techniques are employed.
It is estimated that the use of mass timber products and other emerging wood technologies in buildings 7-15 stories tall could have the same effect as taking more than 2 million cars off the road for one year.
HOW WILL THE FORESTRY INDUSTRY BE IMPACTED BY MASS TIMBER?
The increase of mass timber construction will be good news for the forest sector, as increased demand for these forest products will spur economic development and investment in the establishment of a robust mass timber supply chain, bringing economic certainty to northern and remote communities that rely on the manufacturing of forest products to generate jobs and economic resilience.
WILL MASS TIMBER CONSTRUCTION HARM OR DEPLETE OUR FORESTS?
Forests capture carbon in the atmosphere as they grow, and store it indefinitely. By contrast, the process for manufacturing concrete and steel emits carbon. By harvesting trees when they reach maturity (and when their carbon uptake capacity begins to diminish), the trees – and the carbon they store – can be transformed in to a resilient building material, and the forest can be regenerated with new trees which will be capable of capturing greater amounts of carbon, perpetuating the cycle.
Forests are one of the few tools we have for removing carbon dioxide from the atmosphere, and Canada’s forests are among the largest in the world. According to Natural Resources Canada, the country is home to more than 168 million hectares of forest land independently-certified as sustainably managed. Canada’s comprehensive and rigorous forest management laws and regulations makes it a source of sustainably produced forest products.
At the same time, we must acknowledge emerging forest science information and society’s evolving expectations about forests. Forest management is a complex discipline in which competing ecological, environmental, and societal interests must be balanced. For example, threatened caribou herds in Canada’s north require large areas of undisturbed forest habitat. Thus, harvesting for mass timber must take place in a manner that recognizes such ecological constraints. This is just one instance of competing values which must be considered and balanced in the complex landscape of forest management, and reflected in sustainable forest management certification.
IS THERE A MARKET FOR MASS TIMBER? IS IT ECONOMICALLY VIABLE?
Mass timber brings cost-efficiency to construction. Timber panels are prefabricated and assembled on-site, reducing construction timelines by 25%, and reducing construction traffic by 90%. However, the economic viability of the material is predicated on the supply chain in place to deliver it.
Right now in Canada, the cost of mass timber varies with the region it is used. In areas where an effective supply chain exists, mass timber is a more cost-effective construction material then concrete or steel. As other jurisdictions establish supply chains that are capable of meeting demand, we will see the cost of mass timber building materials become up to 20% less expensive than concrete and steel.
HOW TALL CAN MASS TIMBER STRUCTURES BE CONSTRUCTED?
The tallest mass timber building in Canada is UBC’s Brock Commons, at 18 stories. Presently, two ten-story buildings (at University of Toronto and George Brown College) have been proposed, in addition to other projects, completed and in progress, in many other cities across the country. An 80-story high-rise is proposed for Chicago. More than 20 timber buildings over 50 meters (164 feet) tall are slated to be completed in Europe by the end of 2019.