Do You Vent An Attic Which Has Wet Spray?

 
Thread Tools Search this Thread Display Modes
Old 06-25-2008, 11:50 AM   #1
Pro
 
d-rez's Avatar
 
Trade: general contractor
Join Date: May 2007
Location: Austin
Posts: 201
Rewards Points: 150

Do You Vent An Attic Which Has Wet Spray?


The title says it all. The architect is telling me that an attic that has a wet spray insulation should not be vented. This seems so wrong to me but I am new to the Icynene type insulations? Thanks, -Chris
d-rez is offline  

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ContractorTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

   
 

Old 06-25-2008, 12:06 PM   #2
Pro
 
Joasis's Avatar
 
Trade: General Contractor
Join Date: Mar 2006
Location: Hennessey, Oklahoma
Posts: 7,420
Rewards Points: 2,860

Re: Do You Vent An Attic Which Has Wet Spray?


Is the attic considered to be "conditioned" space, meaning the spray foam is applied to the underside of the roof decking?

__________________
Ladwig Construction
Hennessey, Oklahoma
405 853 1563

Insulated Concrete Homes / ICF's
My Facebook Page
Joasis is offline  
Old 06-26-2008, 06:30 AM   #3
Pro
 
d-rez's Avatar
 
Trade: general contractor
Join Date: May 2007
Location: Austin
Posts: 201
Rewards Points: 150

Re: Do You Vent An Attic Which Has Wet Spray?


Yes, Joasis, insulation would be sprayed in the rafter bays, not ceiling joists. I would not consider it 'conditioned space' though, the intent is not to air condition the attic.
d-rez is offline  
Old 06-26-2008, 06:53 AM   #4
Pro
 
genecarp's Avatar
 
Trade: LI,NY designer, new homes, renovation work, concre
Join Date: Mar 2008
Location: Long Island, NY
Posts: 5,425
Rewards Points: 2,000

Re: Do You Vent An Attic Which Has Wet Spray?


it is a new way of approaching residential insulation, lock the house down, then provide fresh air exchange
__________________
genecarp is offline  
Old 06-26-2008, 09:22 AM   #5
Pro
 
Ed the Roofer's Avatar
 
Trade: Roofing Contractor
Join Date: Dec 2006
Location: NW Suburbs of Chicago
Posts: 7,135
Rewards Points: 2,010

Re: Do You Vent An Attic Which Has Wet Spray?


The architect is following a newer wave of Building Science theory.

Check out www.BuildingScience.org for a lot of information on it.

Ed
Ed the Roofer is offline  
Old 06-26-2008, 07:37 PM   #6
Pro
 
d-rez's Avatar
 
Trade: general contractor
Join Date: May 2007
Location: Austin
Posts: 201
Rewards Points: 150

Re: Do You Vent An Attic Which Has Wet Spray?


Thanks guys. I met with my insulation sub and he confirmed that it should not be vented. -Chris
d-rez is offline  
Old 09-04-2008, 09:31 AM   #7
New Guy
 
rodeo's Avatar
 
Trade: commercial, apt. & mobilehome maiontenance
Join Date: Jan 2008
Posts: 25
Rewards Points: 10

Re: Do You Vent An Attic Which Has Wet Spray?


d-rez brings up a great point with sprayed cellulose.

According to IRC 806.4 (2007 supplement), unvented attics are allowed under certain conditions. It seems like SPF is the only candidate for applying impermeable insulation first on the decking underside. Only SPF has both air and vapor barrier properties.

There is some confusion as to wether sprayed cellulose meets the 806.4 requirements. Its an air barrier but not a vapor barrier. In fact, cellulose abosrbs and holds quite a bit of moisture. It supposedly will dry out during warm months but it sounds a little strange still.

It would be great if sprayed cellulose could be used here instead of SPF, as its much cheaper. I have a suspicion that sprayed cellulose will work but only with increased ventilation compared to SPF. The SPF may be able to take higher humidity loads than the cellulose.

Last edited by rodeo; 09-04-2008 at 09:34 AM.
rodeo is offline  
Old 09-04-2008, 10:07 AM   #8
Registered User
 
JimE's Avatar
 
Trade: carpentry
Join Date: Sep 2008
Posts: 3
Rewards Points: 10

Re: Do You Vent An Attic Which Has Wet Spray?


No venting. Jim.
__________________
Brookfield Maid
JimE is offline  
Old 09-04-2008, 02:57 PM   #9
Preserving the Past
 
Jason Whipple's Avatar
 
Trade: Restoration & Historic Preservation
Join Date: Dec 2007
Location: Cincinnati, Ohio
Posts: 3,562
Rewards Points: 2,032
Send a message via Skype™ to Jason Whipple

Re: Do You Vent An Attic Which Has Wet Spray?


Quote:
Originally Posted by d-rez View Post
Thanks guys. I met with my insulation sub and he confirmed that it should not be vented. -Chris
Now you need to ask if it's open or closed cell insulation. That should start some good debate!

Welcome to the world of Building Science
__________________
Jason E Whipple, General Manager
Historic House Restoration, Cincinnati, Ohio
Facebook | Twitter
Jason Whipple is offline  
Old 09-05-2008, 10:04 PM   #10
Pro
 
CO2Solutions's Avatar
 
Trade: Dry Ice Blasting
Join Date: Apr 2007
Location: Canada
Posts: 247
Rewards Points: 154

Re: Do You Vent An Attic Which Has Wet Spray?


ok, help me out with this one then. I'm working in a crawlspace at the moment in which mould was formed. The space is basically like a minature basement, poured floor and foundation and spray foam on the underside of the flooring. I'm assuming that it would need air flow as well to prevent mould from forming again? air exchanges required in the crawl space?

thanks,

mike

CO2Solutions is offline  


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
seal gable vents after ridge vent installed? tacoma5050 Roofing 41 06-07-2012 07:32 PM
attic fan or ridge vent dlcj Roofing 29 06-15-2010 06:39 AM
Frost inside the attic? SOSSW Roofing 22 04-03-2009 07:26 AM
Gabled attic vent & door Michaeljp86 General Discussion 4 06-13-2008 09:59 PM
Ridge vent issues? apkole Roofing 4 05-08-2007 05:46 PM

Join Now... It's Fast and FREE!

I am a professional contractor
I am a DIY Homeowner
Drywall Talk is for
PROFESSIONAL CONTRACTORS ONLY!

At DrywallTalk.com we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created www.DIYChatroom.com DIY Chatroom is full of helpful advices and perfect for DIY homeowners.

Redirecing in 10 seconds
No Thanks
terms of service

Already Have an Account?