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This report summarizes hygrothermal analysis of specific attics constructed in California. The analysis was done using historical experience, published work in journals and trade publications,… Read More

Unvented-cathedralized attics are known to be advantageous in hot-humid and hot-dry climates, whereby, exterior moisture would be excluded for hot-humid climates, and attic mounted air distribution… Read More

Sealed attic construction, by excluding vents to the exterior, can be a good way to exclude moisture-laden outside air from attic and may offer a more easily constructed alternative for air leakage… Read More

In cold climates, the primary purpose of attic ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow, and to vent moisture that moves from the conditioned space… Read More

Just about everyone in the building industry can be guilty of using building terms loosely, and a prime example is with attics, roof assemblies. You can vent single components, you can vent… Read More

Roofs can be designed and constructed to be either vented or unvented in any hygrothermal zone. Air barrier systems are typically the most common approach, however, air pressure control approaches… Read More

When constructing unvented roofs with asphalt shingles in hot humid climates, a vapor barrier must be installed between the asphalt shingles and the roof deck. Asphalt shingles store water from dew (… Read More

This article was written to tie together and summarize the various papers on unvented conditioned cathedralized attics found on our website. We realize that there is a wealth of information, and much… Read More

Unvented roof systems can be safely used in many different climates. In cold climates, insulating sheathing must be added exterior to the roof sheathing to prevent condensation on the underside of… Read More

Understand when to vent your roof and when not to, and how to execute each approach successfully. Reprinted with permission from Fine Homebuilding, Aug/Sept 2011, pages 68-72.