Wood is one of the first materials used by humans to create architectural living structures. It is easily acquired, manipulated and maintained. Perhaps partly because of its familiarity it has waxed and waned as a popular building material. With new fabrication techniques and products now available, it is possible to use timber in innovative ways, as a structural material or even a replacement for concrete and steel.
Why Mass Timber? New innovations in glue, nail and cross lamination products mean that timber can now be used in “heavy” applications, resulting in shorter construction schedules, while providing safer and cleaner environments on site. Timber can also be easily prefabricated into panel or structural columns, which further condenses construction timelines and minimizes labor costs. Wood has a much higher strength-to-weight ratio than concrete or steel, and when detailed properly, actually performs better in fire testing. Furthermore, mass timber buildings have far greater thermal efficiency, which allows for major energy savings throughout its lifecycle.
Many designers are returning to natural materials such as wood for the inherent aesthetic benefits. Some of this is likely due to its biophilic nature: wood not only helps create a beautiful space, but research has found that it also improves productivity, health, and wellness. While these may seem like subjective benefits, mass timber office buildings on the West Coast are seeing average office rents increase $7 per square foot.
On the sustainability front, mass timber is the only truly renewable construction material, as well as the only material that can remove carbon from the atmosphere for the lifetime of its usage. Increased demand for these new wood products can help revitalize local economies, as well as encourage responsible, sustainable forestry practices. The U.S. construction industry typically imports wood products from Europe or Canada, but this may change with time and the possible passage of S.538 – Timber Innovation Act of 2017 being considered in the US Senate.
Process: In partnership with Arup, Hickok Cole Architects has undertaken a number of design and structural studies to make the case for feasibility for a market in DC, Virginia and Maryland. By investigating both commercial and residential applications we hope to make recommendations to DCRA and other local zoning boards. In 2018 we submitted an entry to the Maine Mass Timber Wilderness Lodge competition to explore structural schemes and programming:
What’s next? We are actively pursuing opportunities and currently have a projects on the boards, as well as compiling an educational presentation about the benefits and details of timber construction, including looking at precedents in Europe, Canada and the United States. This includes pricing, structural, mechanical and fire safety considerations.
If you are interested in a presentation, please contact Melanie De Cola.
Read more in an interview with Holly Lennihan about mass timber applications.
Parallel Strand Lumber: PSL is a composite of wood strands with fibers. The strongest and stiffest engineered wood product available, it is usually the most effective choice for large single beams.
Nail-laminated Timber: NLT is created by stacking dimensional lumber together on its edge and fastening it together with nails. It is cheaper than other options and more widely accepted in building codes because it is simple to make.
Glu-laminated Timber: Glulam is an engineered product made of two or more layers of lumber glued together with the grain of all layers running parallel to the length. Glulam’s size is limited only by the manufacturing and transportation capabilities.
Cross-laminated Timber: CLT consists of several board stacked in alternating directions and glued together. A typical CLT cross-section contains three to seven boards.