There is a brand new movement among architects, builders, and environmentalists positioning Mass timber as the solution to British Columbia’s steel problem. When used correctly, the now trendy building material could have a significant impact on carbon emissions. So why are some British Columbians wary of it?
The problems with steel
The vast majority of commercial buildings are framed with steel. Even residential builders are turning toward steel as an alternative to wood structures, but is steel green? Steel is undeniably strong, and because it’s recyclable, many environmentalists tout it as a residential alternative to wood. It also adds about $4 billion each year to British Columbia’s economy.
Why is steel a ‘dirty’ building material?
Steel is made from metallurgical, or coking, coal. Metallurgical coal is the most valuable mineral currently mined in B.C. The coal mining industry, primarily in the eastern parts of the province, employs thousands of B.C. residents. By and large, Canada is a coal exporter, not a steel manufacturer. Most of the coal mined in B.C. is shipped to Asia, where it’s turned to steel and used in buildings, railways, roads, and bridges. To manufacture steel, metallurgical coal is heated to above 1000 degrees Celsius with no oxygen. It’s then quickly cooled in air or water to produce a hard porous brick called coke. The coke then goes back into a blast furnace, this time at more than 2000 degrees Celsius, where it’s mixed with other ingredients which harden to create steel. To produce a tonne of steel, the manufacturing process creates about 1.85 tonnes of carbon emissions.
Is there a greener building material?
Increasingly, green builders are going back to the construction industry’s roots, so to speak. Wood, once considered too weak and too flammable to safely support commercial structures, is experiencing a transformation.
What is mass timber?
“Mass timber,” short for massive timber, is a new technology that gives wood the strength and fire-retardant properties that rivals steel. Manufacturing techniques vary, but most mass timber is cross-laminated (CLT). To create CLT, manufacturers trim and kiln-dry boards and then glue several layers together, alternating the direction of the grain. CLT slabs are up to a foot thick and come in an almost infinite array of sizes. CLT is fire resistant, earthquake resistant, and strong enough to support a 100 story building. CLT’s benefits don’t stop with the environment. Because CLT is cut to order at the factory, there is virtually no waste. CLT is about ⅕ the weight of steel and concrete; it’s much easier to manage and cuts construction time by about 25 percent. When harvested from sustainable forests, a CLT frame can reduce a building’s carbon footprint by around 27 percent compared to steel and concrete. Because CLT is engineered, it doesn’t require mature trees. Instead, manufacturers can use far more replaceable small and young trees. Using just 20 North American forests, experts estimate that it would take about 13 minutes to grow enough wood for a 20-story building. Seagate Mass Timber is leading the revolution in “Big Wood” being used in all areas of construction. Seagate has offices in British Columbia, Canada, and the US in Washington state. If you have any questions about this article or would like to talk to us about your construction project, please call us at (604) 529-7685.
