Detailed Computer Analysis of the Moisture Performance of Roof Constructions in the U.S. DOE Moisture Control Handbook.
Detailed Computer Analysis of the Moisture Performance
of Roof Constructions in the U.S. DOE Moisture Control
Handbook.
(1887 K)
Tsongas, G. A.; Thornton, B. A.; Burch, D. M.; Walton,
G. N.
Challenges of the 21st Century. Roofing Technology, 4th
International Symposium. Proceedings. First (1st)
Edition. U.S. National Roofing Contractors Association,
Canadian Roofing Contractors Association, National
Research Council of Canada, International Waterproofing
Association, CIB, RILEM. September 17-19, 1997,
Gaithersburg, MD, National Roofing Contractors
Association, Rosemont, IL, 401-416 pp, 1997.
Sponsor:
Department of Energy, Washington, DC
Keywords:
air flow; attics; attic ventilation; building
technology; computer modeling; mathematical analysis;
moisture; moisture analysis; moisture modeling; moisture
performance; roofs; roof cavities; roof ventilation
Abstract:
A new mathematical model, called the MOIST Attic Model,
has been used to predict the moisture performance of a
current practice site-built prototype house with 15
different roof designs constructed in compliance with
the U.S. DOE Moisture Control Handbook in cold
(heating), mixed, and cooling (hot and humid) climates.
These open attic or cathedral ceiling roof constructions
were intended to be the best designs to minimize
moisture problems. But prior to this study, their
moisture performance had not been checked with a
moisture model. Thus this computer simulation study of
their performance was undertaken. For each of the 15
roof designs, attention was focused on predicting the
peak values of the plywood roof sheathing moisture
content and the relative humidity at the bottom of the
insulation adjacent to the various ceilings where mold
and mildew might grow. Parametric sensitivity analysis
was undertaken to determine the effect of a number of
variables on the moisture performance of the various
roofs. Findings of the study regarding the moisture
performance of the 15 designs, as well as roof design
suggestions and code implications, are presented.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899