- Author
- Burch, D. M.
- Title
- Experimental Validation of a Mathematical Model for Predicting Moisture Transfer in Attics.
- Coporate
- National Bureau of Standards, Gaithersburg, MD Department of Energy, Washington, DC
- Book or Conf
- Proceedings of International Symposium on Moisture and Humidity. April 15-18, 1985, Washington, DC, 287-296 p., 1985
- Keywords
- mathematical models; moisture content; residential buildings; wood; roofs; proving; predictions; heating; test chambers; climate; ventilation; water vapor; adsorption; condensing; static tests; dynamic tests; dew point; environment simulation
- Identifiers
- attics
- Abstract
- A small test house having a pitched roof/ventilated attic was installed in a high-bay environmental chamber. The test house and its attic were extensively instrumented for measuring heat and moisture transfer. The test house was subsequently exposed to a series of steady diurnal outdoor climatic conditions. Representative conditions of a residence were simulated within the test house. A mathematical model was developed that included the adsorption of water vapor at wood surfaces in the attic. This model closely predicted the attic dewpoint temperatures for both the steady and dynamic outdoor cycle tests. The model showed that wood surfaces of the attic at a moisture content of 12.5% (by weight) adsorbed water vapor and maintained the wood surface dewpoint temperature below the roof sheathing temperature, thereby preventing condensation.