The construction industry's leading researcher explains why what we think is true often isn't, and how some of our best hunches, based on observation of field performance, have paid off with problem-free attic assemblies
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I've gotten many calls over the years about attics and attic ventilation; almost invariably the caller is confused, having heard different things from different people. In this article, I'll discuss the performance of attic assemblies and try to shed light on why there are so many points of view about roof ventilation.
The temperature of a northern-climate roof we monitored throughout the 1990s is shown below. Here is a summary of the study: The roof gets cold at night and is hot during the day. It gets hotter on a sunny day than on a cloudy day. Attic assemblies with openings to the outdoors ("vented" attics) stay a bit cooler during the daytime than unvented...