Comparative Moisture Performance of Wood/Wood-Based Claddings Predicted by Four Hygrothermal Simulation Tools

A number of hygrothermal (HAM) numerical simulation packages are available, either wholly or partially dedicated to heat, air and moisture transfer simulations of building materials and wall assemblies. The objective of this work was to compare the HAM responses and moisture performance of western red cedar and composite wood claddings of a wood frame wall as predicted by four HAM simulation tools: DELPHIN, WUFI, hygIRC, and COMSOL. Three Canadian cities having different climates were selected for simulation: Ottawa (ON), Vancouver (BC) and Calgary (AB). In each city, simulations were run for two years as selected from a historical climate data set based on the moisture index (MI). The wall orientation receiving the most wind-driven rain for the two years was selected for simulations. Material properties were taken from the National Research Council(NRC) material property database. Cladding temperature and relative humidity (RH) values as well as the moisture accumulated in the entire structure were compared amongst the results obtained from the four tools. The mold growth index on the cladding surface was used as a basis for comparing the moisture performance.