Cross laminated timber (CLT) and its use as a structural wood product is relatively new compared to other engineered wood products. While current design standards for CLT subjected to long term deflection or creep provide a value for the time dependent deformation factor (creep factor), direct validation of such a value has not been conducted. The 2018 version of the National Design Specification (NDS) recommends a creep factor of 2.0 be used for CLT. Eurocode recommends a value equivalent to 1.8 for normal moisture and temperature conditions. To provide a point of comparison to the design values suggested in US standards, full scale long-term deflection testing of CLT panels is being conducted under a variety of load levels. The increasing deflections over time give an indication of the creep factor. This paper describes the short-term destructive tests and the first 3 months of progress of the long-term tests. Preliminary results indicate creep factors approaching values glue-laminated timber and solid sawn lumber in the NDS after the first 3 months.
