Thanks to its air sealing properties, foam insulation for vented attics, particularly in cold and dry climates, helps curb a “stack effect” where heated air escapes through the ceiling (and eventually the attic) and is replaced in lower levels of the home by drawn-in, outdoor air.
Foam insulation for vented attics, placed on the attic floor, can also work to minimize moist warm indoor air from entering the attic and causing potential roof damage from condensation on the roof deck, in addition to other moisture and heat-loss-related problems such as seasonal ice damming and mold growth.
Vented attic code references
Local codes based on IRC 2009: Section R806.1
- Local codes based on IRC 2012: Section R806.1
Foam plastic (spray foam)
- Local codes based on IRC 2009, 2012 and 2015: Section R316
- Energy efficiency of building thermal envelope
- Local codes based on IRC 2009, 2012 and 2015: Section N1102