Energy and Hygrothermal Analysis of Cross Laminated Timber (CLT) Mid-rise Commercial Buildings

Mass timber construction has recently seen worldwide interest and increased use due to its multiple benefits such as structural robustness and high level of prefabrication. While energy and hygrothermal performance of cross laminated timber (CLT) buildings are important key aspects to consider, current literature mostly focused on structural and fire performance. This study compares CLT and steel-stud mid-rise commercial buildings in two cities (Boston, MA and Austin, TX) using hygrothermal performance and building energy simulations software WUFI and OpenStudio. Hygrothermal simulations investigate the drying capability of the multi-layer envelopes when different insulation products (such as stone wool and extruded polystyrene, XPS) are used in exterior wall and roof applications following IECC 2015 code. Building energy modeling comprises parametric analysis including different ventilation modes, insulation systems, and HVAC setpoints. Results include recommendations on what combination of HVAC and envelope system produces highest energy savings and effectively controls moisture in the envelope for new mid-rise constructions with CLT inclusions.