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Jon Davis Posted: Jan 03, 2007 06:38 PM	unvented attic codes short background info -- I am currently remodeling a home and tripling its floorspace. I am also working towards becoming a certified building designer. my question is - how do I get an unvented attic to pass local codes in Maryland? I've had very little luck with the local inspectors returning phone calls. I picked up the 2006 IBC and IRC code books and have been looking through those very closely for anything that would help. I've been told by an architect relative that he had to get his local poly sales rep to provide him with the info to give to the inspector to pass his first unvented attic. thanks for any help.
Luke Kujacznski Posted: Jan 03, 2007 07:02 PM	In Michigan all we had to do was prove that a unvented attic performed better then a vented attic. From my interaction with the inspectors around here there main concern is shingle life and roof deck temp. I think that there is a article out there that is a case study of "hot roofs" in arizona, that states that they had a 10% loss in shingle life. They are different the us northerners in that they have 350 days of sun a year, plus 100+ degree temps all summer. So translate that up here and we have maybe 5% loss in shingle life. Also the measured actual temps, the roof deck on a unvented attic got up to 180 degrees where as a vented attic got up 165. Not much different. I think the article was by Joe Lisbuk( help on spelling) anyone know. Luke
quentin Posted: Jan 03, 2007 10:00 PM	Here you go, all the info you need on the topic. Got to love google! http://www.buildingscienceseminars.com/handouts/BSD-102_Understanding_Attic_Ventilation.pdf
Jon Davis Posted: Jan 03, 2007 10:26 PM	thats a pretty handy artical -- thanks for the help guys
kevin fowler Posted: Jan 22, 2007 08:25 PM	ICC website R-806.4 allows for unvented attics and crawlspaces. This was an ammendment put into code in November 2005. ICC refers to unvented or conditioned attic areas as 15 degrees of the habitable living area. So if you can maintain these temps, and you can, it is acceptable.

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Comments

Jon Davis

Posted: Jan 03, 2007 06:38 PM

unvented attic codes

short background info --
I am currently remodeling a home and tripling its floorspace.
I am also working towards becoming a certified building designer.

my question is - how do I get an unvented attic to pass local codes in Maryland? I've had very little luck with the local inspectors returning phone calls. I picked up the 2006 IBC and IRC code books and have been looking through those very closely for anything that would help.

I've been told by an architect relative that he had to get his local poly sales rep to provide him with the info to give to the inspector to pass his first unvented attic.

thanks for any help.

Luke Kujacznski

Posted: Jan 03, 2007 07:02 PM

In Michigan all we had to do was prove that a unvented attic performed better then a vented attic. From my interaction with the inspectors around here there main concern is shingle life and roof deck temp. I think that there is a article out there that is a case study of "hot roofs" in arizona, that states that they had a 10% loss in shingle life. They are different the us northerners in that they have 350 days of sun a year, plus 100+ degree temps all summer. So translate that up here and we have maybe 5% loss in shingle life. Also the measured actual temps, the roof deck on a unvented attic got up to 180 degrees where as a vented attic got up 165. Not much different. I think the article was by Joe Lisbuk( help on spelling) anyone know.

Luke

quentin

Posted: Jan 03, 2007 10:00 PM

Here you go, all the info you need on the topic. Got to love google!

http://www.buildingscienceseminars.com/handouts/BSD-102_Understanding_Attic_Ventilation.pdf

Jon Davis

Posted: Jan 03, 2007 10:26 PM

thats a pretty handy artical -- thanks for the help guys

kevin fowler

Posted: Jan 22, 2007 08:25 PM

ICC website R-806.4 allows for unvented attics and crawlspaces. This was an ammendment put into code in November 2005. ICC refers to unvented or conditioned attic areas as 15 degrees of the habitable living area. So if you can maintain these temps, and you can, it is acceptable.

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