By 1997, several field surveys in North America had indicated that rain penetration in exterior walls and poor construction detailing contributed to the shortening of the service life of recently built exterior walls of low-rise buildings in climates with high exterior moisture loads. There was a movement in industry to rethink the ways that exterior walls had been put together in recent years, as well as a renewed appreciation that exterior climates vary in severity from one location to another. In 1998, IRC/NRC initiated a research consortium with industry partners to develop guidelines for moisture management for exterior wall systems (MEWS) in low-rise residential buildings of North America. Partners represented the wood industry, manufacturers of cladding systems, insulation materials and water resistive barriers as well as building owners and managers. The project was broken down into several tasks, from a review of literature on current construction practice to experimental work in the laboratory and mathematical modelling. The following four types of cladding systems were included in the project: Portland cement plaster (stucco), Exterior Insulation and Finish Systems (EIFS), masonry and siding, over wood-frame construction. This TG8 report is a research document. The objectives of the report are three-fold: to describe the research approach in some detail (chapter 1), to summarize its application to the four types of wall assemblies (chapters 2 - 5) and to draw general conclusions (chapter 6), based on the observations in chapters 2 - 5. The reader is strongly advised to consult the research team before the information presented in this report is used for building design considerations.

All authors: Beaulieu, P.; Bomberg, M.; Cornick, S.; Dalgliesh, A.; Desmarais, G.; Djebbar, R.; Kumaran, K.; Lacasse, M.; Lackey, J.; Maref, W.; Mukhopadhyaya, P.; Nofal, M.; Normandin, N.; Nicholls, M.; O'Connor, T.; Quirt, J.; Rousseau, M.; Said, M.; Swinton, M.; Tariku, F.; van Reenen, D.

• experiment: facility on moisture in building envelope
• experiment: hygrothermal performance
• HAM hygrothermal simulation
• HAM: application
• HAM: computer models : hygIRC
• wind driven rain
• WRB weather-resistive barrier, house wrap

1. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
2. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America  

1. Analysis of selected water absorption coefficient measurements
2. Building envelope and environmental control - Part 3: Issues of system integration
3. Building envelope and environmental control: issues of system integration
4. Building envelope design, Part 2: estimating field performance of thermal insulation
5. Building envelope: Heat, air and moisture interactions
6. Heat, air and moisture control in walls of Canadian houses: a review of the historic basis for current practices
7. In-Situ performance evaluation of exterior insulation basement systems (EIBS) - spray polyurethane foam: summary report
8. Integrated Methodology for Evaluation of Energy Performance of the Building Enclosures -- Part 1: Test Program Development
9. Integrated methodology for evaluation of energy performance of the building enclosures: part 3 ˇŞ uncertainty in thermal measurem
10. Modified cup for testing of water vapour transmission through thick, permeable materials
11. Moisture management of EIFS walls. Part 1.The basis for evaluation
12. Performance evaluation of exterior insulation and finish systems (EIFS)
13. Position paper on material characterization and HAM model benchmarking
14. Report from Task 2 of MEWS Project - Description of 17 Large Sale Wall Specimens Built for Water Entry Investigation in IRC Dynamic Wall Testing Facility
15. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
16. The energy conundrum of modern buildings
17. Three-dimensional analysis of thermal resistance of exterior basement insulation systems (EIBS)
18. Towards an engineering model of material characteristics for input to ham transport simulations - Part 1: an approach
19. Water vapor transmission and moisture accumulation in polyurethane and polyisocyanurate foams
20. Water vapor transmission through building materials and system: mechanisms and measurement  

1. A comparison of empirical indoor relative humidity models with measured data
2. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
3. A moisture index to characterize climates for building envelope design
4. Climate loads and their effect on building envelopes - an overview
5. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
6. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
7. Report from Task 4 of MEWS Project - Environmental Conditions, Final Report
8. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America  

1. Report from Task 4 of MEWS Project - Environmental Conditions, Final Report  

1. Building Physics: 3rd International Conference in Building Physics
2. Building pressurisation can affect possibility of mould growth
3. Comparaison de m¨¦thodes de mesure de flux de chaleur pour sp¨¦cimens de grandes et moyennes dimensions
4. Experimental setup for the study of air leakage patterns
5. Impact of added insulation on air leakage patterns
6. Impact of added insulation on the hygrothermal performance of leaky exterior wall assemblies
7. Impact of air leakage pattern on reinsulated walls
8. Mapping of air leakage in exterior wall assemblies
9. Moisture performance of leaky exterior walls with added insulation
10. Report from Task 2 of MEWS Project - Description of 17 Large Sale Wall Specimens Built for Water Entry Investigation in IRC Dynamic Wall Testing Facility
11. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
12. Study of the reduced impact of thermal bridges in two sprayed-applied polyurethane wall assemblies  

1. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
2. Environmental boundary conditions for long-term hygrothermal calculations
3. Indoor and outdoor weather analysis tool for hygrothermal modelling
4. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
5. Report from Task 4 of MEWS Project - Environmental Conditions, Final Report
6. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
7. Use of hygrothermal numerical modeling to identify optimal retrofit options for high-rise buildings  

1. A comparison of different techniques to quantify moisture content profiles in porous building materials
2. Determination of the liquid water diffusivity from transient moisture transfer experiments
3. Effect of surface temperature on water absorption coefficient of building materials
4. Final report from task 7 of MEWS long-term performance: predict the moisture management performance of wall systems as a function of climate, material properties, etc. through mathematical modelling
5. Influence of air space on multi-layered material water vapor permeability measurement
6. Influence of sheathing membrane and vapour barrier on hygrothermnal response of stucco walls
7. Integrated analysis of whole building heat, air and moisture transfer
8. Modeling moisture accumulation in multi-layered building materials, MODELING MOISTURE IN RESIDENTIAL BUILDINGS WITH A MULTIZONE IAQ PROGRAM
9. Moisture management of EIFS walls. Part 1.The basis for evaluation
10. NIST/NRC-Canada interlaboratory comparison of guarded hot plate measurements: 1993-1997
11. Summary Report from Task 3 of MEWS Project at the Institute for Research in Construction - Hygrothermal Properties of Several Building Materials
12. Transient model for coupled heat, air and moisture transfer through multilayered porous media  

1. A discrete stochastic model for performance prediction of roofing systems
2. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
3. An approach to validating computational models for hygrothermal analysis - full scale experiments
4. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
5. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
6. Durability of Building Materials and Components 8
7. Executive Summary of Research Contributions Related to Moisture Management of Exterior Wall Systems (MEWS) - Modeling, Experiments, and Benchmarking
8. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
9. Proposed method for calculating water penetration test parameters of wall assemblies as applied to Istanbul, Turkey
10. Report from Task 2 of MEWS Project - Description of 17 Large Sale Wall Specimens Built for Water Entry Investigation in IRC Dynamic Wall Testing Facility
11. Report from task 6 of MEWS project -- experimental assessment of water penetration and entry into wood-frame wall specimens, - final report
12. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America