Assessing termite impact on cross-laminated timber panels
Cross-laminated timber, or CLT, is a mass timber product relatively new to the North American market. An environmentally sustainable alternative to pre-cast concrete panels for modular construction, CLT is a customizable product, able to be assembled by smaller construction crews in less time than traditional construction methods. Interest in this product is spreading rapidly across North American markets; however, no data quantifying the impact of native and invasive termites on the product have yet been published. Also, no standards exist for testing CLT against termites. The Forest Service’s Forest Products Laboratory and the Mississippi State University’s Department of Sustainable Bioproducts are currently conducting lab and field trials to provide data to manufacturers, architects, and construction professionals. CLT prepared with kiln-dried lumber and polyurethane adhesive was exposed to the Formosan termite in a laboratory trial over eight weeks. The Formosan termite is an invasive species of subterranean termite. The average weight loss and the visual rating for the CLT blocks (6.01 percent and 7.5, respectively) were similar to the results found for the untreated blocks (7.19 percent and 8.0 respectively), indicating moderate to severe attack with termite penetration into the block. A comparison group of blocks treated with a wood preservative had less than a 4 percent mass loss and no visual ratings less than 10, indicating a sound, unaffected block. An ongoing field trial will be examined in October 2017 for comparison. By generating this data, the Forest Products Laboratory and the university hope to provide guidance for the use of CLT in climates where pressure from subterranean termites is high.
Forest Service Partners