For several decades now, every major building code has
required roofs to be ventilated. While other areas of the
codes have changed and evolved, roof venting rules
have remained unchallenged.
Recently, though, some building scientists have been
questioning the need for roof ventilation. In researching this
article, we pored over many pages of research data, including
studies from the United States, Canada,
and Sweden. We also considered the experiences
of builders who have been trying
out a variety of unvented, or "hot roof,"
designs. Our conclusion is that the strongest
evidence, both from the lab and from experience
in the field, continues to support the
importance of ventilation.
A Little History
According to researcher Bill Rose