Like most industries, construction is evolving with a common goal of making the process smarter for increased productivity, precision, and efficiency. Done right, these changes lead to better building with more control over costs.

As the awareness of Mass Timber grows, it is quickly becoming an innovative method of construction worth considering. Within the mass timber family, Cross-Laminated Timber (CLT), is an emerging wood style of construction proving to be a highly advantageous alternative to concrete, masonry, or steel in commercial construction.

CLT panels are formed by stacking and gluing successive perpendicular layers of solid wood panels. With its multi-layer, bi-directional design, this mass timber product is dimensionally stable and has inherent load-bearing and shear strength. It’s no wonder architects, builders, and turnkey commercial framers are giving CLT the serious attention it deserves.  Read more on how CTL is impacting commercial construction in our earlier blog. 

To date, the majority of CLT projects are using wood in horizontal applications such as floors and roofs. But as we build, we learn. CLT is now proving to be a game-changer for vertical applications, including elevator and stair towers which are typically built using concrete masonry or CMU. A quick comparison of the two methods demonstrates the value of incorporating CLT into traditional building structural systems.

Among the most notable advantages is time. An elevator tower designed with CLT can be installed in a few hours versus weeks when using masonry. For a building that calls for 6 to 8 shafts, it is possible to save weeks on the project. When the wood framing partner incorporates a tower crane, the shafts can be erected simultaneously with the wall panels, which further maximizes efficiency and lessens the amount of manpower needed on the job site. When you reduce the time of the build and the people needed, you save money.

A commercial construction project that incorporates CLT stair and elevator towers with turnkey, prefabricated panelized framing could save between two and six months, depending on the size of the project. As an example, six months in general conditions could equate to approximately $600,000.

Another notable benefit to using CLT for elevator and stair towers is its fire-resistant properties. Like heavy timber, mass timber has inherent fire resistance that allows the wood to be exposed, while still achieving the two-hour fire-resistance rating. Fire resistance is measured from the start of the fire up until the point that the material is no longer functional. Resistance is measured in minutes: FR 30, 45, 60, or 120. To achieve the designed fire resistance period, each CLT panel within the building must be designed for the fire-resistance period and the specific loading applied to that panel. Fire resistance testing of CLT panels is to ISO 834, which is the same standard used for doors. Additionally, the char rate of wood has been well documented and the 2018 International Building Code (IBC) identifies CLT as an approved, fire-resistant building material.