Skip to Main Content
FPL roof temperature and moisture model : description and verificationAuthor(s): A. TenWolde
Source: (Research paper FPL ; RP-561):48 p. : ill. ; 28 cm.
Publication Series: Research Paper (RP)
Station: Forest Products Laboratory
PDF: View PDF (467 KB)
DescriptionThis paper describes a mathematical model developed by the Forest Products Laboratory to predict attic temperatures, relative humidities, and roof sheathing moisture content. Comparison of data from model simulation and measured data provided limited validation of the model and led to the following conclusions: (1) the model can provide reasonably accurate estimates for temperatures of roof sheathing and attic air, although heat storage effects often cause delay of 1 to 2 h in attic air temperatures; (2) the model can accurately predict the frequency of occurrence of high roof sheathing temperatures (> 120*F (49*C)) during summer, but accuracy is highly dependent on solar absorptance and emissivity values of the roof shingles; (3) the model consistently overpredicts the extent of night-time cooling from sky radiation losses, leading to predicted temperatures that are too low; (4) treatment of the effect of snow cover is too simplistic, but no better alternatives are apparent for simulating this very complex behavior; (5) the model apparently can predict average moisture conditions in the sheathing with reasonable accuracy, generally within 1% moisture content, when moisture content is not excessively high or low; and (6) hourly moisture behavior is not represented as well as is daily or seasonal behavior, especially for north-facing sheathing. The model would benefit from verification with data that include measured emissivity and solar absorptance of the shingles, addition of thermal mass in attic and roof, better algorithms to calculate direct and diffuse solar radiation, and verification for roof with east1west orientation.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationTenWolde, A. FPL roof temperature and moisture model : description and verification. (Research paper FPL ; RP-561):48 p. : ill. ; 28 cm.
KeywordsRoofs, Temperature, Moisture, Relative humidity, Mathematical models, Computer software, Attics, Heating
- Roof temperatures in simulated attics
- Thermal load histories for North American roof assembles using various cladding materials including wood-thermoplastic composite shingles
- Two-year Wisconsin thermal loads for roof assemblies and wood, wood–plastic composite, and fiberglass shingles
XML: View XML