Mass timber is revolutionizing the construction industry, offering a more sustainable alternative to building materials like concrete and steel.
Moving Away From Wood
Humans have been building with wood for centuries. As the world urbanized and industrialized, we began to build more and more dense cities. After the Great Chicago Fire of 1871, which left over 100,000 people homeless, North American perceptions of wood as a "safe" building material shifted. Commercial, industrial, institutional, and high-density residential buildings transitioned away from wood toward concrete and steel, with wood-framed buildings only used for smaller "light construction" roles, like single family homes.
Moving Back to Wood
The first mass timber products were developed in the 1990s in Austria, and were originally designed for light residential construction. By the 2010s, North American architects and builders began adapting the technology for use as a replacement for concrete and steel in larger buildings. In 2015, mass timber was adopted in to the International Building Code.
Manufacturing Process
Mass timber is manufactured by bonding multiple layers of wood together to form larger structural components like panels or beams. The process typically involves two primary techniques:
Cross-laminated timber (CLT)
Large structural panels are created by stacking layers of dimensioned lumber (like 2x6 boards) at right angles and bonding them with structural adhesive. This is often used as a replacement for a poured concrete wall.
Glue-laminated timber (glulam)
Long continuous beams are made by gluing many smaller pieces of lumber together. These can be more cost effective than beams sawn from a single timber, since they can use smaller, low quality trees instead of large old-growth.
Fire Concerns
One common misconception about mass timber is its fire resistance. While wood is combustible, mass timber has inherent charring properties that provide natural fire resistance. During a fire, the outer layers of mass timber components develop a protective char layer, which slows down the burning process and insulates the structural core. Additionally, mass timber's predictable charring behavior allows engineers to design structures with fire safety measures in mind.
Regulatory Barriers
As mass timber gains popularity, regulatory frameworks are evolving to accommodate this building material. One of the biggest discussions in the industry is how high we can build with mass timber. Currently, the National Building Code of Canada only allows mass timber structures up to 12 stories.
The world's tallest Mass Timber structure is 18 stories and is located in Norway. However, an 80-storey tower is proposed for Chicago. Yes, THAT Chicago. The city whose devastating fire sparked the original transition away from heavy wood construction in the late 1800s.
Environmental Sustainability
There are two primary arguments for the sustainability of mass timber products: carbon storage, and lower carbon emissions from manufacturing.
Carbon Storage
When trees grow, they capture and store carbon. When they die and decompose, some of that goes into the soil, and some goes into the atmosphere. If a tree is cut down and turned into a building product, that carbon is effectively "stored" inside the building for the life of the structure.
Lower Emissions
Concrete and steel are both carbon intensive to produce. Steel is made by burning coal at high temperatures to melt iron ore. Cement for concrete is made by burning heavy fuel oil, coal or natural gas to dehydrate lime. Both industries are massive carbon emitters. To learn more about the environmental cost of concrete, check out this blog post.
In contrast, logging is significantly less carbon-intensive, and the industrial processing of timber products does not require the same intense heat as steel or concrete production, making the use of renewably-sourced electricity more viable.
Just Part of The Solution
These benefits are only part of the story. There are never truly "quick and easy" solutions to building greener structures and improving environmental sustainability. The forestry industry in BC is far from perfect, and forest products that are harvested without a sustainable, responsible, long-term forest management plan can lead to deforestation and devastation of ecosystems. BC Premier David Eby recently described the province's forests as "exhausted", saying the forestry sector has never been under greater stress than it is currently.
The Future of the Industry
If we can achieve sustainable and responsible forest management, the future looks promising for mass timber. As the demand for more eco-friendly building solutions grows, mass timber is poised to become a prominent player in the construction industry.
Mass Timber in the Kootenays
Located near Nelson, BC, the new $35 million Kalesnikoff mass timber facility is a prime example of the growing presence of mass timber in Canada. This state-of-the-art facility showcases advanced manufacturing processes, including precision milling and automated assembly lines, to produce high-quality mass timber products.
Key Points
Traditionally only smaller buildings, like houses, have used wood for structural components.
Mass Timber products are an alternative to building materials like steel and concrete.
They are being used in larger scale commercial, industrial, and institutional buildings.
Mass Timber products have a smaller environmental footprint than the materials they replace, and can actually store carbon.
These benefits are promising, but must be combined with proper forest-management plans to truly be considered "sustainable".
The Kootenays are actually a leader in the North American Mass Timber market.
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