Moisture Control: Convective Drying in Residential Wall Systems
Pennsylvania State University
* Eric F. Burnett, Principal Investigator
Start: September 15, 2001
Expires: August 31, 2003
Moisture constitutes a hazard for buildings and their occupants. There are at least two good reasons to ensure that the presence and movement of moisture across the enclosure of buildings is controlled, especially the exterior walls of houses: first, to avoid the health hazards (mold, etc.) and, second, to avoid deterioration of the materials within the wall. Controlling moisture requires knowledge of how wetting, storage, and drying occur, as well as some idea of the performance thresholds for the materials involved. For many building professionals and educational institutions, this is a new science.
This project is directed at understanding, modeling, and evaluating the potential for ventilation and convective drying within various wall systems. Houses with pitched roofs commonly make use of the circulation of air to remove moisture from the attic space; hence the familiar vented roof with both soffit and ridge vents for letting cold, dry air in and warm, moist air out in the winter. The contribution of convection to the drying of walls needs to be much better understood.
This project will contribute to improving the durability and the safety of wall systems in houses, leading to reduced maintenance and repair costs. The project meets more than one of the stated PATH goals. The most important involves computer modeling and the investigation of a number of design and development issues. Practical concerns are: sizing the flow chamber; assessing the contribution of sheathing membranes (house wrap, building paper); and venting strategies and how best to transfer the technology to the various target audiences, namely the researchers, design professionals, manufacturers, and the house builder community.
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Content updated on 9/21/2005