In a composite wall, each constituent component plays a specific role in effective moisture management. The moisture movement to and from the wall assembly, subjected to climatic forces, such as relative humidity (RH), temperature, rainfall and solar radiation, is influenced by the basic hygrothermal properties of the component materials. Studies conducted at the National Research Council (NRC) Canada, over the years, show that the hygrothermal properties of materials vary over a wide range. Quite naturally, such variation may influence the overall moisture response of the wall. This paper investigates the extent to which each component of the wall can influence the overall drying and wetting characteristics of an ideal (i.e., without any deficiency) wood-frame stucco wall when it is exposed to weather conditions typical of coastal Western Canada. The component materials selected include stucco, sheathing board, a sheathing membrane and a vapour barrier. Hygrothermal material properties compiled in the laboratory at the NRC and the hygrothermal modelling tool, hygIRC, developed by the NRC, are used for this purpose. The findings of this study indicate that, with further work and analysis, practical guidance could be developed to assist designers and engineers to identify the critical components and properties of the stucco wall assembly to achieve a desirable moisture management strategy for the building envelope.

Other

Kumaran, M.K.; Wang, J. "How well should one know the hygrothermal properties of building materials ?" Proceedings of CIB W40 Meeting (Prague, Czech Republic, 8/30/99), pp. 47-52, August 30, 1999

• simulation of building process
• WRB weather-resistive barrier, house wrap

1. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
2. Determination of equilibrium moisture content of building materials: some practical difficulties
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 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 logical extension of the ASTM Standard E96 to determine the dependence of water vapor transmission on relative humidity
3. A methodology to develop moisture management strategies for wood-frame walls in North America: application to stucco-clad walls
4. A thermal and moisture transport property data base for common building and insulating materials (final report)
5. Application of gamma-ray spectroscopy for determination of moisture distribution in insulating materials
6. Benchmarking of the advanced hygrothermal model hygIRC with mid scale experiments
7. Building envelope design, Part 2: estimating field performance of thermal insulation
8. Criteria for unaccesseptable damage on wood systems
9. Determination of equilibrium moisture content of building materials: some practical difficulties
10. Durability assessments of wood-frame construction using the concept of damage-functions
11. Effect of exfiltration on the hygrothermal behaviour of a residential wall assembly: results from calculations and computer simulations
12. Final Report, IEA-Annex 24, Task 3: Material Properties
13. Indoor and outdoor weather analysis tool for hygrothermal modelling
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. Indoor and outdoor weather analysis tool for hygrothermal modelling
2. Influence of sheathing membrane and vapour barrier on hygrothermnal response of stucco walls
3. Summary Report from Task 3 of MEWS Project at the Institute for Research in Construction - Hygrothermal Properties of Several Building Materials
4. Use of hygrothermal numerical modeling to identify optimal retrofit options for high-rise buildings