Bill Durch
5/15/2009
Icynene foam insulation is becoming more common in Texas homes. It is applied directly to the underside of the roof deck between the rafters and the attic is sealed from the exterior, no ventilation at all. My question is regarding composition asphalt shingles over Icynene. I've always been of the understanding that composition shingles need air flow under the deck to prevent the shingles from deteriorating too fast. If the insultaion was batt a 1 inch air gap is required between the roof deck and fiberglass. Should this not be the same for icynene? Thank you.
Todd Miller
Isaiah Industries, Inc.
5/15/2009
I think to a large degree the jury is still out on this one. Non-vented attics do not meet many building codes but they are good building science. I am not sure whether such practices affect the warranty on asphalt shingles.
Guest User
3/15/2010
I am an architect in Huntsville Alabama. Today I started researching non-vented attics. What information I have found says you have to buy the right kind of shingle. Not any shingle will do due to the higher temperatures occuring in the shingle of a non-vented attic.
Eric Novotny
An informed customer is the Best Customer!
3/16/2010
I am aware of no special asphalt shingle for un-vented attics. Better yet, don't put asphalt on your roof in the first place. Shingle temperatures on an un-vented attic are usually only +3-5 degrees warmer than their vented counterparts. Most shingle cooling occurs to outside air. More important to shingle cooling is pitch of the roof rather than attic ventilation.
Guest User
4/7/2010
Can you please give me your source of the 3 to 5 degree of increased temperature for shingles in a non vented attic? I'm researching this for someone buying a 60 year old house in south FL. & it's really difficult for me to believe that a good flow of air under the roof deck does not reduce the shingle temperature more than that. Thanks
Eric Novotny
An informed customer is the Best Customer!
4/7/2010
http://docs.google.com/viewer?a=v&q=cache:DybZ74IWM0YJ:www.buildingscience.com/documents/reports/rr-9701-measurement-of-attic-temperatures-and-cooling-energy-use-in-vented-and-sealed-attics-in-las-vegas-nevada+Measurement+of+Attic+Temperatures+and+Cooling+Energy+Use+in+Vented+and+Sealed+Attics+in+Las+Vegas,+Nevada&hl=en&gl=us&pid=bl&srcid=ADGEESjC1TJNiA_2Nbyx_ZQCVbTSWQ9PtlswjZtgeHfgKtlGITrWm7MRONpUB7F7NmujWcdOoFkw2OMK1u5WumfEl8gafvyGMtZLYCkz8wGQNsVnO5LV6XYIIQ1sH4-lBu9uW6eRggRj&sig=AHIEtbSjA0PWFq_AiJwF_DnScodDHQa7dA
Eric Novotny
An informed customer is the Best Customer!
4/7/2010
www.buildingscience.com
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