Is Wood the Future of Sustainable Multifamily?
Mass timber is the latest in sustainable construction materials for the apartment industry.
In Cleveland, Harbor Bay Real Estate Advisors is developing its first mass timber project. With an exterior clad in wood, the nine-story project will feature 298 units, 40,000 square feet of retail and 340 parking spaces. In order to make this innovation possible, a change in the city’s building code was required.
“Developers, architects, engineers and labor must be willing to embrace innovation and not be fearful of change,” said Harbor Bay CEO Mark Bell. “In addition, our government bodies on the federal, state and local levels need to make the pathway for mass timber easier and more accessible, including the supply chain, manufacturing and code acceleration.”
As the multifamily industry makes more of an effort to provide a greener lifestyle for its residents and to do its part toward a greener world generally, mass timber construction is gradually being accepted by developers and building commissioners for its sustainability and other benefits.
“Mass timber” describes wood products that combine laminations of multiple layers to achieve a stronger hold than traditional lumber. These include cross-, nail- and glue-laminated timber, which can all be used depending on the type of project. Mass timber can be used on its own or in conjunction with more traditional materials such as steel or concrete.
“Everyone has realized as climate becomes more challenged and carbon is more of an issue, wood is the only material that sequesters that out of the atmosphere,” said Robert Glowinski, president & CEO of the American Wood Council.
Additionally, processes used to make wood use biomass energy, which is carbon neutral. The energy used to make those products has lower impact vs. the more intensively used fossil fuel-based energies in other materials. A study by the Yale School of the Environment and the University of Washington College of the Environment found that using more wood and less steel and concrete in building construction reduces global carbon emissions and fossil fuel consumption.
Mass timber can also be made from smaller-diameter trees and those impacted by insects and disease. This creates incentives for forest thinning—which reduces the potential for wildfire—and for private landowners to keep forested lands forested.
“Fifty-eight percent of forests are privately owned, so having a high-value end use for this material provides a financial motivation to keep lands forested,” said Jennifer Cover, president & CEO of WoodWorks, a nonprofit that provides education and free support related to the design, engineering and construction of wood buildings in the U.S. “That’s a key driver in its sustainability, the fact that landowners invest in the health of their forests and keep replanting trees. It increases the value of the forest and, because mass timber products have such high strength, allows for smaller trees to be used in massive structures.”
According to data from The United States Department of Agriculture, the total volume of trees growing in U.S. forests has increased 60 percent since 1953.
The sustainability of mass timber construction is just one of its many useful features. According to the American Wood Council, construction time on mass timber building is reduced up to 25 percent compared to other materials. It also offers 90 percent less construction traffic and requires 75 percent fewer workers.
Projects in the works
WoodWorks maintains a map of 921 mass timber projects constructed or in design across the U.S. Although a large majority can be found within the Pacific Northwest, due to its closer proximity to warehouses, there is a surprisingly large amount located in the South and Northeast as well.
Another mass timber project in the works is 340+ Dixwell in New Haven, Conn. Beulah Land Development is leading the team along with H.E.L.P. Development and Spiritos Properties LLC. The architect is Gray Organschi and Schadler Selnau.
The 69-unit project, which will be the first affordable housing property of its kind, has received needed special exceptions and variances from the Board of Zoning Appeals and is set for completion in two years after needing to go through a financing bonding process and a site plan review.
Jeff Spiritos, principal of Spiritos Properties LLC, noted that the point of the project is to “show that this holistic cost approach, when combined with quality of the apartments created and sustainable benefits, are a more affordable way of building than stick frame lumber, which is currently the least expensive way to build housing.”
Milwaukee is set to receive the tallest mass timber tower in the world. New Land Enterprises, Korb + Associates Architects and Thornton Tomasetti are working on Ascent. The 21-story, mixed-use project will comprise 410,000 square feet in downtown. The building will stand 238 feet tall when completed.
Although mass timber construction seems to be catching on, it still comes with challenges. Unfortunately, there aren’t many mass timber sources in the country. If developers get their materials from China or the Pacific Northwest for a project in Florida, they lose some reduced carbon emission benefits during transportation to the construction site. If there isn’t a source nearby, developers could lose some value through transportation costs, as well.
Another struggle comes with finding the right team. “You need to find architecture, engineering and contractors familiar with mass timber. Otherwise, you’re paying for them to pick up the learning curve,” said Marta Schantz, senior vice president for the Greenprint Center for Building Performance at the Urban Land Institute.
Since the main thrust of mass timber is carbon sequestration, developers looking to utilize mass timber also need to make sure they’re in an environment where they are sequestering more than the carbon that is being used. Carbon is stored in the forest, so they need to store more than what is used. Typically, developers are most concerned with comparing the cost of mass timber to other building materials.
There is also the issue of whether or not local codes allow construction of mass timber projects, which cannot surpass eight stories in most locations. The newer codes that will go into effect next year will give specific permissions within that seven- to-12-story window. Some cities and states have already adopted these codes early on, including Utah, Denver, Washington, Oregon and, most recently, California.
The good news for developers is that, even if a mass timber product was to end up being more expensive in the short-term, the entire building could be the same price or less when all benefits are considered: reduction of waste, shortening of the construction period, faster occupancy and increased comfort among residents due to the material’s biophilic elements.
The production time of Carbon 12, a mass timber multifamily project in Portland, for example, was reduced from 19 to eight weeks. This was because the property was constructed in a modular installation that led to less construction time on site due to its prefabrication, explained Schantz.
Additionally, having natural wood pieces exposed throughout major areas of the community brings residents in touch with nature, providing biophilic experiences. Wood in the ceilings, walls, columns and beams, for example, have been shown to reduce asthma, increase concentration and manage humidity.
When the new codes are set in place in 2021, there should be more interest in the long-term use of these materials that will not only save on time and construction costs but also improve the environment.