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PRIORITYSPRAYFOAM  

Q&A Forums Registered User
Posted: 2/13/2010 11:40 AM EST

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Roof Baffle Required?
Hi Mason,

Working with a couple to spray closed cell SPF under the roof deck to have an "Unvented Attic". In speaking with their builder/contractor the following question was raised:

"We just met with a builder and he wants us to do a baffle vent (1” sister beams along rafters, adhere plywood to beams to create channel with airflow that enters into the drip edge vent up through the baffle channel and out the ridge vent.) He feels the roof will just overheat without it. He is also the guy who is going to personally put in our new roofing on the existing frame. We cannot find studies done or articles written by independent third parties that mitigate this venting concern."

What would you explain to the builder/contractor and the homeowners, and what supporting documents, if any, is there?

Thanks

foamdude

Q&A Forums Registered User
Posted: 2/14/2010 6:03 AM EST

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RE: Roof Baffle Required?
(waiting for mason's lead here,,,probably at daytona),,,
there is much lit on the conditioned lids with spray foam and shingle temps/ice dams/life expectancy ect..
many are from the roof/shingle industry themself,,many by roof industry building scientists and recognized "experts",,,and not from the spf industry...
all positive to the conditioned lid assembly..
spend some time on the puker and you will find these,,like any search,,broaden your querey if you arent finding what you need,,the info is readily available,,,
do a search here as well as this topic has been hammered on many times @spryfmdotcom...

let me see if i have the docs on the portable drive down here in chilly orlando,,if so i will forward what i have,,but it may be on the office puker back in the waycold cornfield..
ps:send money,,,rofl
'dude

Mason  

Moderator
Posted: 2/14/2010 12:39 PM EST

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RE: Roof Baffle Required?
This subject came up recently and we supplied quite a few arguments about the issue. Main factor is that the unvented attic concept does not significantly affect the temperature of shingles and does increase the potential for condensation.

Email me at masonknowles@aol.com and I will send you some research and articles to help refute the theory that unvented attic assemblies are detrimental to shingle life and wood decks.

I am at the annual Sprayfoam conference til the 18th and my laptop has decided to not connect to the internet, so I will have to provide the information when I get back.

In the meanwhile, see articles on my website, masonknowles.com and check out documents by Joe Lstiburek and associates at buildingscience.com

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