FoamRun strongly promotes the use of unvented attic assemblies. There are numerous advantages to this approach. Unvented attics will eliminate ice damming on the roof, ensure that HVAC equipment and ductwork will be located in conditioned space, and will usually provide a tighter building envelope. When the thermal boundary is located at the attic deck level, access to the attic, recessed light fixtures, and bathroom exhaust fans can pose considerable challenges to a tight building envelope.
Have a look at the articles listed in the sidebar to further explore the benefits of the unvented attic assembly.