Sustainability is a hot topic in the world + in the design community. Sustainability in regards to mass timber is an even more hotly debated topic.
Are mass timber buildings actually more sustainable than other buildings?
This question doesn’t have a straight-forward answer, and a lot of variables should be evaluated when considering a mass timber structure if sustainability is one of your main objectives.
How to assess a sustainable structure
A life cycle assessment (LCA) is often run to measure a building’s Global Warming Potential (GWP) along with other environmental impacts. Those results are compared with a similar building constructed with other materials to determine the preferred construction material option for each scenario. We recently did this for the Cincinnati Public Radio project which we’ll tell you about more later, but for now, let’s consider other aspects of sustainability that may not be directly measured by a life cycle assessment.
Healthy forests
What sustainability comes down to – carbon. Healthy + growing forests are an essential component in transforming carbon into oxygen. One could argue that nothing is more important to the health of our world than keeping healthy forests. With this in mind, the majority of the forests in the United States are privately owned. The owners often need financial incentives to keep these forests thriving instead of converting them into something else like farmland. Therefore, keeping a demand for forestry, and both the harvesting + replanting of trees, is essential to give the owners a return on investment AND ultimately keep the forests healthy. Hence, all wood construction projects, including mass timber projects, help to drive that essential demand.
Health + wellness
Speaking of health, health + wellness of those who spend time inside of the building is an important + sustainable aspect of mass timber.
We should not only be concerned about the health of our planet, but we should also take into consideration the health + well-being of those inside.
From my perspective, it’s difficult to enter a mass timber building and leave without a smile on my face. But it’s not just my opinion – there’s an entire approach, called biophilic design, that focuses on nature + wellness-focused design including how natural wood elements affect occupant well-being. Check out these stats on how exposed wood office buildings affect well-being.
- “Developers also are seeing higher leasing velocity and/or lease rates for offices with natural wood environments. The developer for Clay Creative, a timber office building in Portland, Oregon, reports that tenants were willing to pay $7 more per square foot annually than a similar non-wood structure located across the river downtown.”
- “Those in workplaces with a higher proportion of visible wood feel more connected to nature, and rate their working environment far more positively. These people report higher concentration, lower stress levels, and improved overall mood.”
- “There is a close connection between the rate of employee absenteeism, their satisfaction at work, and the presence of wood in their workplace.”
The same logic can be used for housing. This also increases the likelihood the building will maintain a useful life for a longer period of time and ultimately improve the results of a mass timber building on the life cycle assessment.
A whole building life cycle assessment is one way to measure sustainability for a structure, and other aspects are often + should be evaluated (for example, occupant well-being, natural lighting, landscaping, etc.) for a holistic look at the sustainability equation.
Cincinnati Public Radio life cycle assessment
Let’s return to our Cincinnati Public Radio project as we promised above. The new Cincinnati Public Radio headquarters will be one of the first mass timber building in Cincinnati, Ohio, and will be an incredible addition to the Keystone Parke development, Cincinnati’s first LEED-certified corporate campus. The two-story facility nearly doubles Cincinnati Public Radio’s previous space and will have offices, broadcast suites, a publicly accessible podcast studio and spaces for live events.
In performing the life cycle assessment on Cincinnati Public Radio with its architect, Emersion Design, we compared mass timber vs. steel construction. And the results were (DRUMROLL) mixed.
*These data points were specific to the Cincinnati Public Radio project and do not represent a complete list for comparing mass timber + steel construction materials.
Cincinnati Public Radio chose to move forward with a mass timber structure because it’s immediate sustainability benefits, erection speed, and the transformational aesthetic for its employees + the local community.
How mass timber can become more sustainable
Aside from Global Warming Potential, mass timber structures can perform poorly in a life cycle assessment in the end of life stage. Why? Because some life cycle assessment models, including what was used for Cincinnati Public Radio, assume no reuse of the material at the end of a building’s useful life, whereas a material like steel is typically recycled. If mass timber ends up in a landfill or burned, the carbon stored in the material will be released back into the atmosphere and the temporary carbon sink will ultimately be of little benefit.
The main challenge before the design community is to figure out what to do with the mass timber material at the end of life. If we can crack the nut of material reuse, then we can also crack the nut of improving the overall sustainability of a mass timber building.
