Effective moisture control in the building envelope is essential if acceptable service life is to be achieved for the built environment. Effective moisture control implies both minimizing moisture entry into the system, and maximizing the exit of moisture, which does enter, so that no component in the system stays 'too wet' for 'too long'. But what is "too wet" and "too long"? At the institute for Research in Construction, National Research Council of Canada, a research project called MEWS (Moisture Management for Exterior Wall Systems) was initiated to answer the above questions. The project has now resulted in a methodology that leads to design considerations for improved moisture management strategies for any wall assembly at any geographic region in North America. The methodology includes the integration of information from a review of field practices (Rousseau et al., 2002), extensive measurements of hygrothermal properties of building materials (Kumaran et al., 2002), definition of environmental loads (Cornick et al., 2002), investigation on damage functions (Nofal and Kumaran 1998), experiments on wind-driven rain penetration (Lacasse et al., 2001) and a detailed parametric analysis using a benchmarked and advanced hygrothermal model called hygIRC (Maref et al.2001; Mukhopadhyaya et al. 2001). This paper attempts only to summarize the methodology and lists some of the observations from its application to stucco-clad (Portland cement plaster) wood-frame walls. A full description of each module in the methodology is beyond the scope of this paper 2.

• HAM: theory and modelling
• moisture control, moisture management

1. A comparison of empirical indoor relative humidity models with measured data
2. A logical extension of the ASTM Standard E96 to determine the dependence of water vapor transmission on relative humidity
3. A thermal and moisture transport property data base for common building and insulating materials (final report)
4. Application of gamma-ray spectroscopy for determination of moisture distribution in insulating materials
5. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
6. Building envelope design, Part 2: estimating field performance of thermal insulation
7. Criteria for unaccesseptable damage on wood systems
8. Determination of equilibrium moisture content of building materials: some practical difficulties
9. Durability assessments of wood-frame construction using the concept of damage-functions
10. Effect of exfiltration on the hygrothermal behaviour of a residential wall assembly: results from calculations and computer simulations
11. Final Report, IEA-Annex 24, Task 3: Material Properties
12. Indoor and outdoor weather analysis tool for hygrothermal modelling
13. Influence of material properties on the moisture response of an ideal stucco wall: results from hygrothermal simulation
14. In-Situ performance evaluation of exterior insulation basement systems (EIBS) - spray polyurethane foam: summary report
15. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
16. Modeling heat, air and moisture transport through building materials and components
17. Moisture buffering capacities of five North American building materials
18. Moisture diffusivity of building materials from water absorption measurements
19. Moisture transport coefficient of pine from gamma ray absorption measurements
20. On implementing experimental biological damage-functions models in durability assessment systems
21. Prediction of moisture response of wood frame walls using IRC's advanced hygrothermal model (hygIRC)
22. Protecting the long-term performance of building envelope components
23. Report from Task 4 of MEWS Project - Environmental Conditions, Final Report
24. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
25. Taking guess work out of placing air/vapor barriers
26. Three-dimensional analysis of thermal resistance of exterior basement insulation systems (EIBS)
27. Use of hygrothermal numerical modeling to identify optimal retrofit options for high-rise buildings
28. Vapor transport characteristics of mineral fiber insulation from heat flow meter measurements
29. Water vapor transmission and moisture accumulation in polyurethane and polyisocyanurate foams  

1. Determination of equilibrium moisture content of building materials: some practical difficulties
2. Effect of surface temperature on water absorption coefficient of building materials
3. 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
4. Influence of material properties on the moisture response of an ideal stucco wall: results from hygrothermal simulation
5. Influence of sheathing membrane and vapour barrier on hygrothermnal response of stucco walls
6. Prediction of moisture response of wood frame walls using IRC's advanced hygrothermal model (hygIRC)  

1. A comparison of empirical indoor relative humidity models with measured data
2. A moisture index to characterize climates for building envelope design
3. Climate loads and their effect on building envelopes - an overview
4. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
5. Final Report from Task 8 of MEWS Project (T8-03) - Hygrothermal Response of Exterior Wall Systems to Climate Loading: Methodology and Interpretation of Results for Stucco, EIFS, Masonry and Siding Clad Wood-Frame 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. A discrete stochastic model for performance prediction of roofing systems
2. An approach to validating computational models for hygrothermal analysis - full scale experiments
3. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
4. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
5. Durability of Building Materials and Components 8
6. Executive Summary of Research Contributions Related to Moisture Management of Exterior Wall Systems (MEWS) - Modeling, Experiments, and Benchmarking
7. Final Report from Task 8 of MEWS Project (T8-03) - Hygrothermal Response of Exterior Wall Systems to Climate Loading: Methodology and Interpretation of Results for Stucco, EIFS, Masonry and Siding Clad Wood-Frame Walls
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  

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

1. An Overview of the Survey of Building Envelope Failures in the Coastal Climate of British Columbia, Performed by Morrisson-Hershfield Limited for CMHC (1996)
2. Creating durable bonds between windows and walls
3. Designing exterior walls according to the rainscreen principle
4. Heat, air and moisture control strategies for managing condensation in walls
5. Moisture management: prediction of response of exterior wall elements to climates
6. Monitoring the hygrothermal performance of a masonry wall with and without thermal insulation
7. 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
8. Review of factors affecting the durability of repointing mortars for older masonry  

1. Criteria for unacceptable damage on wood systems
2. Criteria for unaccesseptable damage on wood systems
3. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
4. Durability assessments of wood-frame construction using the concept of damage-functions
5. On implementing experimental biological damage-functions models in durability assessment systems  

1. A moisture index to characterize climates for building envelope design
2. BLWT, CFD and HAM modelling vs. the real world: bridging the gaps with full-scale measurements
3. Defining climate regions as a basis for specifying requirements for precipitation protection for walls
4. MEWS methodology for developing moisture management strategies: application to stucco-clad wood-frame walls in North America
5. Report from Task 8 of MEWS Project - MEWS Methodology for Developing Moisture Management Strategies - Application to Stucco Clad Wood-Frame Walls in North America
6. Thermal Bridges -- Heat flow models with HEAT2 HEAT3, and a general purpose 3-D solver
7. Wind on Buildings