Development of a modified standard termite test for mass timber products

Abstract

U.S. manufacturers are looking to expand the use of cross laminated timber panels (CLT) into the North American market, including states located in the southeast. However, there is no current assessment method for determining CLT vulnerability to the highly destructive native termites found throughout the U.S. The impact of these termites is particularly high in areas with suitable climate to their proliferation, such as the southeastern U.S. This study aimed to evaluate durability of CLT panels and to develop a laboratory assay to test susceptibility of this product to termites. Untreated CLT suffered mass loss of up to 43.8% in testing with an average visual rating of 7.2, indicating a moderate to severe attack with 10 to 30% of the cross-section of the product affected by termite intrusion.  Recommendations were developed for inclusion in standardized testing protocols and will be presented to standards organizations as appropriate. The proposed method can also be applied to evaluate termite resistance of other mass lumber products such as parallel strand lumber, laminated veneer lumber, and Glulam.