In recognition of National Forest Products Week, the Environmental and Energy Study Institute (EESI) held a briefing about an innovative class of structural wood building materials, known as mass timber, which is poised to open up new markets for sustainable, domestic forestry products. Mass-timber products, such as cross-laminated timber (CLT) (dubbed "plywood on steroids"), consist of lumber panels layered and joined together, creating a strong, safe, and sustainable building material.
Melissa Jenkins, Wood Innovations, U.S. Forest Service
- Cross-laminated timber (CLT) is a type of mass timber that involves layering wood from small diameter trees to create a strong, lightweight building material. Strength is achieved by gluing each layer perpendicular to the last.
- The U.S. Forest Service has a stake in promoting mass timber. One hundred years of fighting forest fires has left many forests too dense, especially with small-diameter trees, creating conditions that fuel intense wildfires.
- Mass timber creates an economic incentive to use forests sustainably while leaving them intact, making communities safer while also developing local economies.
- CLT was developed 25 years ago in Austria and Germany and appeared in the United States in 2015. The first two U.S. companies, Smartlam and D.R. Johnson Lumber, are expanding operations, and other firms are forming around mass timber.
- Mass timber language (the Timber Innovation Act) is included in both the House and Senate versions of the 2018 Farm Bill.
- The U.S. Forest Service (USFS) supports mass timber projects through partnerships with universities, communities, and nonprofits like WoodWorks, which provides free technical support and educational resources to those interested in using mass timber. Additionally, USFS began the Wood Innovations Grants program in 2015, which expands wood markets and promotes wood as a building material through funding assistance to a handful of projects each year.
- The U.S. Forest Service also helped raise awareness for mass timber, sustainable forestry, and the economic importance of forests through support for the public television documentary series America's Forests with Chuck Leavell.
Craig Rawlings, President & CEO, Forest Business Network
- Existing CLT manufacturing facilities form an important part of the economies of small towns, creating quality, higher-skill jobs. The further development of the industry will provide more opportunities in the future.
- CLT is not limited to specific species of trees. The product can be made from the trees that are available in a particular area.
- The annual International Mass Timber Conference has seen attendance skyrocket over the last few years, reflecting an increased interest in the technology and its future.
- Mass timber creates economically viable products that can incentivize land managers to use small diameter wood, thereby creating multiple benefits environmentally and economically.
Susan Jones, FAIA, Architect, Owner and Founder, atelierjones, LLC
- CLT provides a lower carbon, renewable alternative to traditional building materials like steel and concrete. Additionally, healthy forests store carbon, as do materials made from wood.
- Domestically, there are many examples of beautiful mass timber buildings throughout the states of Oregon and Washington, including residential homes, schools and a church.
- Recent material testing in the United States, as well as existing examples of tall wood buildings in other parts of the world, demonstrate that such buildings are safe. The International Building Code will likely change in the coming months to remove many obstacles to tall wood buildings. This is good news, as the greatest potential for mass timber construction is in building more sustainable mid-rise and high-rise buildings.
- The adhesives used to create CLT have been around for a century, and do not release harmful gases that are associated with the production of some other building materials.
- Mass timber is not just an exciting new use for an old material—it’s a way to protect forest health and build sustainably.
Jeff Morrow, Construction Manager, Timber & Innovations Group, Lendlease
- Lendlease is a construction management and development group with 13,000 employees across four continents.
- CLT can be an attractive option for a variety of projects for different reasons, including geological conditions, as well as scheduling and labor constraints. One project, International House in Sydney, chose mass timber because of weight restrictions associated with building over an underground parking structure.
- Leadlease has been involved with constructing a variety of modern timber buildings, including office spaces, living complexes, and company headquarters. These projects have been completed under diverse climate conditions (including a cold and snowy New York state winter).
- Blast testing performed at Tyndall Air Force Base in Florida showed that CLT is exceptionally durable, and it is now being used in some of Lendlease’s military construction projects, including several army hotels.
- CLT construction provides multiple benefits and attributes: it is a lightweight construction material that is blast and fire resistant and has good seismic values.
The unique properties of mass timber differentiate it from light-frame construction and include fire safety, resistance to seismic and explosive forces, thermal performance, and aesthetics. A light, renewable material, its use not only lowers carbon emissions from the building sector but also provides long-term carbon storage—turning buildings into carbon sinks. Policymakers are interested in mass timber for its role in rural economic development, forest health and preservation, resilient infrastructure, and climate change mitigation. This briefing brought together experts to tell the emerging story of the U.S. mass timber industry and how to capitalize on its potential.
Already, the U.S. Department of Defense, universities, architects, and builders around the country are using mass-timber products for a variety of buildings. CLT and other prefabricated mass-timber products save construction time and can be either the predominant building material or combined with other building materials. Changes to U.S. building codes currently being considered could spur use of mass timber for taller buildings in compact urban areas. Mass timber could significantly change the fabric of our cities, offering unique environmental, performance and design attributes.
Europe and Canada currently make up the majority of the global cross-laminated timber market, but the domestic market is growing due to the availability of sustainable forestry stocks and interest from building industry professionals and clients. Dozens of mass-timber buildings are in the planning or building stages around the United States, and 12 CLT facilities or processing facilities are operational or in development in eight states (AL, IL, ME, MT, OR, TN, UT, WA).
The 2018 Senate Farm Bill contains provisions from the Timber Innovation Act, which would advance domestic research and development of the various applications of structural wood in the building sector.