Experimental and numerical investigations of the effects of air leakage on temperature and moisture fields in porous insulation

• An insulated ceiling section subjected to air leakage is tested experimentally.
• Good agreement between experimental measurements and numerical models is obtained.
• The developed HAM model could be used to detect interstitial condensation.

Air leakage through the building envelope can lead to an increase in energy consumption and to potential moisture damages. This paper investigates the impact of air leakage on the hygrothermal field in a ceiling section insulated with blown-in cellulose, and separating an attic space from a heated indoor space. This ceiling section, part of a full scale test-hut built in the Environmental Chamber of Concordia University, is tested experimentally with and without air leakage. The temperature in the cellulose is measured at different locations along the air leakage path and compared with temperature outputs from recently developed HA (Heat Air) and HAM (Heat Air Moisture) numerical models. The HAM model, which shows good agreement with experimental data, is finally used to perform an analysis of the hygrothermal field in the cellulose. The ability of this HAM model to calculate 2D-hygrothermal fields in the presence of airflow is helpful to predict consequences of poor workmanship or bad design and to move toward moisture safe buildings.