Hygrothermal Characterization and Impact of Drainage Positive Fibrous Insulation for Above Grade Exterior Insulation Application

The push towards high-performance buildings has been the new approach of the Canadian building construction market for environmental sustainability and energy conservation. Generally, high performance buildings are designed with exterior insulation, which needs to be examined through the lens of heat and moisture transport. Currently, there are no integrated simulation models that designers can use to measure the drying rate of drainage positive insulation. This research focused on hygrothermal analysis associated with drainage positive exterior fibrous insulation for the above-grade application. The research occurred in two phases: the first phase investigated characteristics of the drainage positive insulation material, and the second phase investigated long term UV and bulk water performance, and drainage performance of the insulation material. Phase one involved four experiments: temperature-dependent moisture content, complete and partial immersion, temperature and moisture-dependent vapour permeance, and temperature and moisture-dependent thermal conductivity. The results from these experiments showed that fibreglass adsorbed more moisture compared to mineral wool insulation. Additionally, the results indicated that fibreglass had lower permeability and higher thermal conductivity than mineral wool insulation. Phase two included two experiments: UV and bulk water deteriorated material performance, and in-situ drainage test. The results showed that the deteriorated sample showed higher moisture sorption and vapour permeance. The in-situ drainage test revealed that before excessive bulk water exposure, the insulation samples were completely dried in 24 hours.