Title: CONDENSATION CONTROL IN CONCRETE MASONRY WALLS - NCMA
Headings: CONDENSATION CONTROL IN CONCRETE MASONRY WALLS
CONDENSATION CONTROL IN CONCRETE MASONRY WALLS
INTRODUCTION
CONDENSATION
Restricting Water Vapor Flow
CONDENSATION CONTROL
Recommendations by Climate Zone
All Climates
Cold and Very Cold Climates
Hot-Dry & Mixed-Dry Climates
Hot and Humid Climates
Mixed-Humid Climates
Marine Climates
DETERMINING CONDENSATION POTENTIAL
BASEMENTS
References

Content: When warm moist air comes into contact with a cold surface, the air cools and can no longer hold all of its water vapor—the excess moisture condenses. Local cold spots in a wall can cause small areas of condensation. Cold spots are usually caused either by thermal bridging or by air leakage. Both can be avoided with appropriate design strategies. See TEKs 6-13B Thermal Bridges in Wall Construction and 6-14A Control of Air Leakage in Concrete Masonry Walls (refs. 1, 2) for more detailed information. Restricting Water Vapor Flow
Water vapor can move through building envelope assemblies by diffusion and via air leakage, so both mechanisms must be considered. The amount of water vapor that travels via air movement can be several orders of magnitude greater than that due to diffusion. Therefore, limiting air leakage is an important water vapor control strategy. For detailed information on reducing air leakage, see TEK 6-14A. When an air barrier material is required, the vapor permeability of the material must be evaluated relative to the material’s location within the wall to help ensure that the air barrier material is not contributing to moisture problems due to vapor diffusion.