Wood is good (Part 1): 7 reasons to consider wood construction on your next project
December 03, 2018
December 03, 2018
Safety, resilience, and versatility are all advantages that mass timber can offer compared to steel and concrete
Brought on by unprecedented technological advancements in manufacturing, the building construction industry is experiencing a wood building revolution. The demand for wood—either as a structural component or as an exposed interior element—has boomed over the last decade, driven by a new awareness of its beneficial properties along with advances in technology that have increased its possible application.
Like any building material, wood has its limitations. But overall, its benefits extend well beyond its value as a sustainable material. There are several good reasons to use wood on your next project. Let’s look at seven.
Mass timber has a variety of characteristics making it a contender in today’s building industry—many of which deserve more attention. Often prized for its beauty and warmth, structural wood’s acoustic properties, seismic resilience, moisture buffering, and thermal conductivity are all superior to that of steel or concrete.
But, what about safety? By far the greatest obstacle facing wood structures is their perceived vulnerability to fire. This is usually due to the confusion between mass timber structures and light timber frames (think of a typical two-by-four from the hardware store).
Light timber frames, comprised of small lumber sections, are always protected by gypsum or other fire-resistant materials to achieve any degree of fire protection, meaning they remain vulnerable during construction. Sprinklers may be required for light timber buildings. This method of fire protection is inefficient and costly for mid- and high-rise structures.
Enter mass timber. With typical section widths of at least 200 millimetres (7 to 8 inches), mass timber members resist fire due to their girth. When exposed to fire, a charring layer forms on the exterior of the member, insulating and protecting the interior from immediate damage. Tests show that fire weakens mass timber at a slower rate than it does steel.
Moreover, mass timber doesn’t deform significantly when exposed to extreme temperatures the way steel does. This means that in the event of a fire, the building structure will remain stable over a predictable time period of exposure—a characteristic greatly appreciated by first responders. Like light timber frames, steel often has to be encased and protected for fire resistance. These measures are simply unnecessary with mass timber.
Today, engineered structural wood members are now available in nearly all shapes and sizes, providing designers greatly expanded applications for use of wood. Now available in a wide range of products with interesting mechanical and structural properties, wood is adaptable to almost any type of structure.
The versatility and beauty of wood can be seen in our Mistissini Bridge project in northern Québec. This project had very limited site accessibility and choosing wood as the main component for the bridge’s structure allowed us to source the material locally. This enabled us to manufacture wood components more quickly than if we’d fabricated from steel and concrete and support the local economy in the process.
One of the most beneficial commercial advantages of a wooden structure is the achievable speed of construction. Mass timber elements—such as posts, beams, and solid panels used as load-bearing walls and floor slabs—can be detailed and machined in-shop and quickly assembled when they arrive on site. This considerably reduces construction time relative to traditional on-site carpentry.
In addition, once a given portion of the structure is assembled and secured, other trades can commence their scope of work. This is a significant advantage when compared to the curing time and formwork removal delays when erecting a typical concrete structure. A high level of prefabrication with on-site assembly produces less noise and jobsite waste than the average worksite, reduces public disturbance, and is extremely well suited for year-round construction.
The construction of Murray Grove in London in 2008 showed us the speed at which a modern tall residential mass timber building could be constructed—at just 49 weeks for the 29-apartment tower by a team of four people.
University of British Columbia’s Brock Commons tower—on which Stantec served as mechanical/electrical and LEED consultant—was erected in less than 70 days and four months ahead of schedule. These savings are critical when construction turnaround time is a driving factor for the economic viability of a project.
Mass timber is lightweight yet strong—4 to 7 times lighter than concrete and 15 to 22 times lighter than steel.
Mass timber is lightweight yet strong—4 to 7 times lighter than concrete and 15 to 22 times lighter than steel. This often makes its use the most suitable solution for construction projects where foundation costs can skyrocket due to the need for piles or the improvement of existing soil conditions. When building on a site with relatively poor soil conditions, wooden structure construction often proves to be the most cost-effective solution.
What’s healthier for the earth also turns out to be healthier for us, as shown by a growing number of studies on the positive effects of exposed wood on the human environment.
"We can say that wood reduces stress in a person and has a calming effect. This is based on the positive emotional experience that wood causes, such as proximity to nature, warmth, homeyness, and a relaxing effect," explains Marjut Wallenius, Doctor of Psychology at the University of Tampere, Finland.
These health benefits can be game changers when it comes to choosing the right building material.
Exposed wooden structures also offer a warm and elegant architectural finish. Our affinity for this material comes as much from our cultural and historical heritage and elegant wood structures in our communities as our innate love of nature sometimes called biophilia.
If we can source the wood component near the project site, we engage local labor, which stimulates the local economy. Moreover, there is often a transfer of knowledge to the local workers who gain new skills, helping them to improve and grow their business. Plus, there’s the possibility for increased visibility and business opportunities for the local firm.
Wood is a sustainable material. Whether we are building with pine or oak, wood is a far greener option than either concrete or steel. The harvest and production of wood building product consumes less energy than steel or concrete.
Just as importantly, it’s renewable. Today’s wood can be grown and harvested responsibly in managed forests. Wood can save even more energy if it’s locally sourced, reducing transportation needs. The wood building process itself is also less energy-intensive than the conventional method.
It’s no surprise that our client, the City of Montreal, chose wood as its main material to build its first Net-Zero and LEED Gold reception pavilion at Parcours Gouin Trail Net-Zero Energy Pavilion in 2016, making it a technological and educational showcase promoting sustainable development to the community. The use of 95% Forest Stewardship Council (FSG)-certified wood alongside 31.5% regionally-sourced material and 10% recycled content all contributed to reducing the building’s ecological footprint.
There are cultural reasons that wood resonates with us so strongly. This natural material that has been part of our heritage since the colonial era, delivering beautiful, elegant, and enduring structures that enrich our community’s landscape. It’s clear to me that wood has significant benefits for all parties involved in project development. When holistic planning takes place in the early stages of a project, it’s possible to harness the economic and sustainable features of this natural material to their fullest.
In part two, we’ll look at how mass timber construction can generate cost savings.