Air leakage through the building envelope can result in large energy penalties but also have detrimental effects on the moisture durability of materials. Researchers have utilized computer simulations to estimate the risk of moisture damages due to air leakage through wall and roof assemblies. However, the accuracy of these simulations has limitations, as they typically employ a onedimensional approach even though airflow-related problems are two or three dimensional. Furthermore, the flow rate and direction of the air that are used in these assessments are usually subjective values. To improve on previous research, this paper describes how to calibrate one-dimensional simulation tools through theoretical equations so that they can be used to study twodimensional effects.

Further, the present work provides guidance on how to use indoor and outdoor boundary conditions to estimate the air's flow rate and direction using existing hygrothermal simulation tools. The proposed method will allow researchers and designers to drastically improve their assessments of the effects of air leakage on the moisture durability of wall and roof assemblies.