What is Cross Laminated Timber (CLT)?

Cross Laminated Timber, or CLT, much like plywood, is composed of many layers of wood glued together so that the strength of the grain is oriented in perpendicular directions. This process gives CLT many of its beneficial properties along with the ability to be panelized.

The wooden layers of CLT are made up of kiln-dried sawn lumber of various thicknesses, but are typically 1.375” thick in the United States (because planed 2x lumber is the easiest to use). Typically, CLT is made of an odd number of layers in order to maintain a symmetrical layup and even strength. These prefabricated panels can be used as load-bearing floors, roofs or walls, and are between 4” – 12” thick.

CLT is a relatively new building system that originated in Austria over 20 years ago and is widely used in Europe. Its popularity quickly spread to Canada and now is penetrating the U.S. market. Because of CLT’s strength, many doors have been opened to allow wood buildings to compete again with mid and high-rise concrete and steel buildings.

Why use CLT?

The potential use of CLT panels in construction in the United States offers an exciting and sustainable wood-construction alternate to a market that is traditionally built with structural steel and concrete systems. CLT panels have a wide variety of structural and architectural benefits, including:

• exposed structural aesthetics
• thermal and air infiltration protection
• thermal mass
• negative carbon footprint
• low structural weight
• excessive strength
• inherent fire protection
• dimensional stability
• prefabricated construction quality
• speed and efficiency of construction

CLT does not have to be used as a single source structural system, and it is often most economic to use CLT in combination with other types of structural framing members such as glulam beams, dimensional lumber or other even other structural materials. Learn more about why CLT should be considered for your next project.

Ask an Expert

Britt, Peters’ team of engineers has a constant focus on emerging technologies and building systems. As such, we have intentionally invested time and resources into advanced timber technologies, with a specific interest in the use of CLT panels as a structural system in the United States. Our staff has completed academic research as well as multiple formal presentations on the potential for use of CLT panels in the U.S. – including most recently the INNOVATE ARKANSAS: Timber and Wood Design, Construction, and Production symposium hosted by the University of Arkansas. Learn more about Britt Peters’ research partnerships here

In addition to the research and education process, we have also completed the design of two projects utilizing CLT panels as their structural system. Construction was completed in July 2017 for one two-story classroom building, and a six-story housing project will be starting construction late summer 2017. The design process for these two projects has given us a unique background and understanding of the effective design, detailing, and sourcing of this product – which coupled with our background in the design of various projects, allows us to provide insight into how to effectively analyze CLT panels as a potential structural and building system.

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