CONTEXT: Uncontrolled moisture accumulation in a building envelope reduces the structural integrity of its components through a combination of mechanical, chemical and biological degradation. Damage induced by moisture ingress includes rotting of wood studs and wood-based sheathing, as well as other detrimental effects such as efflorescence and spalling of masonry, and rusting of fastening mechanisms. Over the past decade, a significant number of low-rise wood-frame residential buildings have been plagued with water penetration problems related to uncontrolled moisture accumulation in the building envelope. In the majority of cases, the reported problems are in coastal areas such as lower mainland of BC, Maritime Provinces and eastern US. Effective moisture control is essential for an acceptable service life of building envelope. Effective moisture control implies both, minimising moisture ingress to prevent ingress of moisture into the inner most fabric of the wall assemblies, and redirection of moisture to the exterior. The principal objective is not to allow any component within the system to stay 'too wet' for 'too long'. The challenge would be to qualify and quantify what is considered "too wet" and "too long"? To address the above challenges, the Institute of Research in Construction (IRC), other industry groups, and stakeholders have established the Moisture Management on Exterior Walls Systems (MEWS) consortium. The objective of MEWS is to determine the minimum characteristics and levels of performance of various wall elements in handling rain water ingress depending on the surface environment of the wall assembly. Experimental work was conducted, both at mid-scale and full-scale levels in order to validate the results obtained through the Advanced Hygrothermal Model hygIRC. Such models allowed the prediction of hygrothermal effect on various wall assemblies at any desired environment conditions, and helped to suggest design considerations to manage moisture in building envelopes.

• PCA -- Principal component analysis
• research, funding : MEWS
• Resource: institutes, organization, associations : NRC IRC
• service life prediction

1. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
2. A precision weighing system for helping assess the hygrotherma response of full-scale wall assemblies
3. An approach to validating computational models for hygrothermal analysis - full scale experiments
4. Assembly and Calibration of a Compact Temperature and Relative Humidity Sensor
5. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
6. Executive Summary of Research Contributions Related to Moisture Management of Exterior Wall Systems (MEWS) - Modeling, Experiments, and Benchmarking
7. In-Situ performance evaluation of exterior insulation basement systems (EIBS) - spray polyurethane foam: summary report
8. Three-dimensional analysis of thermal resistance of exterior basement insulation systems (EIBS)