A new shaft wall system—made from cross-laminated timber (CLT) panels—could be the next big thing in elevator construction, with the US Army leading the way in using the Sterling Solutions-designed system, which offers a cheaper, faster-to-install, and far less carbon-intensive alternative to poured concrete or masonry.
Wood Central understands that the new system uses prefabricated timber in the shaft walls and, in some cases, the roof and does not compromise the lift shaft’s fire safety or structural integrity: “It’s easy to overlook the elevator shaft when considering building materials for a project,” said Michaela Harms, Vice President of Mass Timber at Sterling Structural.
“Yet it’s often the easiest, most cost-efficient and quickest way to reduce cost and embodied carbon across a project. Our new system makes it turnkey to construct your shaft walls from domestically sourced and manufactured, sustainable CLT that reduces cost and time to installation without sacrificing performance, structural integrity or fire resistance.”
New system meets the US Military’s Anti-Terrorism and Force Protection requirements.
Recently deployed as part of the Candlewood Suites Hotel – a new six-story mass timber hotel constructed at the US Army’s Fort Bragg base in Fayetteville, North Carolina, the new system was used in the hotel’s elevator and stair shafts: “We’ve been incredibly impressed with how much time this product saves when installing CLT mass timber walls, especially stair and elevator shafts,” according to Lee Grawcock, senior project manager of MLP Solutions who installed the timber.
“Not only does it eliminate the need for interior drywall to meet the 2-hour fire rating, which is a huge win, but it also integrates seamlessly with all the structural systems we work with, including cold-formed steel, precast concrete, and traditional metal deck systems. It also streamlines site work by not having to schedule a mason/concrete subtrade. The installation process is straightforward and efficient, making it a real game-changer for our carpenters to drive the critical path of our projects.”
Last year, Wood Central reported that the US Department of Defence (and the State Department) were “blast testing” different mass timber construction systems as part of a push to use more and more timber in government buildings.
“Surprisingly, cross-laminated timber is pretty blast resistant,” according to Kevin Naranjo, National Program Manager for Mass Timber at the US Forest Service Wood Innovations Program, who said departments want to deploy technologies that make buildings more blast resistant: “Blast testing will be a game-changer, not just for the military but for construction more generally.”
In late 2023, the US Army Corps of Engineers mandated a policy that requires a “mass timber structural option to be considered at the design phase in all of its vertical construction projects going forward.” In effect, the US Army has become the world’s first military organisation to embrace mass timber in on-site installations and civilian housing projects.
CLT-based wall panels can outperform traditional masonry shaft walls in several ways – because unlike poured concrete or masonry, cross-laminated timber is:
- Lower Cost: CLT panel installation does not require as much labour nor the use of multiple tradespeople;
- Not Weather Dependent: CLT panels can be installed in all weather conditions, enabling more predictable scheduling and maintaining project timelines;
- Quicker to Install: Prefabricated panels can be installed in hours, by a single trade and require only a single inspection
- Sustainable: Sterling’s CLT panels are made from 100% domestically grown, regenerative timber dramatically reducing embodied carbon and supporting the health of US forests
- Generates WELL AP Credits. When left exposed in stairs, CLT generates WELL AP credits by making stairs biophilic which encourages people to take the stairs which leads to healthier lifestyles.
