Cross-laminated timber (CLT) is a wood panel typically consisting of three, five, or seven layers of dimension lumber oriented at right angles to one another and then glued to form structural panels with exceptional strength, dimensional stability, and rigidity. CLT can be manufactured to customized dimensions and panel sizes vary by manufacturer while length is usually limited by transportation restrictions.
Since CLT panels resist high racking and compressive forces, they are particularly cost effective for multi-story and long-span diaphragm applications. Some specifiers view CLT as both a product and a system that can be used interchangeably with other wood products; it can also be used in hybrid applications.
Because of CLT’s structural properties and dimensional stability, this mass timber product is well suited to floors, walls and roofs used in mid-rise construction. The wall and floor panels may be left exposed in the interior which provides additional aesthetic attributes. The panels are used as prefabricated building components which can speed up construction practices or allow for off-site construction.
Currently, US building codes do not explicitly recognize mass timber systems, but this does not prohibit their use under alternative method provisions. In the 2015 IBC, recently approved changes will streamline the acceptance of CLT buildings. The 2015 IBC recognizes CLT products when they are manufactured according to the Standard, ANSI/APA PRG-320: Standard for Performance Rated Cross Laminated Timber. In addition, CLT walls and floors may be permitted in all types of combustible construction, including Type IV buildings.
Get the CLT Handbook to learn more and get technical information for the implementation of CLT systems in building codes and standards.