Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 04-22-2011, 01:17 PM   #1
Newbie
 
Join Date: Apr 2011
Posts: 12
Share |
Default

Wind wash - soffit question?


I am finishing an addition and i am wondering about the wind wash. Do i fill in the entire opening between the trusses, top to bottom and side to side? Or, do i leave a gap at the top so air can circulate between the soffit and the attic? If i leave a gap, how much of a gap do i leave?

BusterMN is offline   Reply With Quote
Old 04-22-2011, 06:15 PM   #2
Member
 
Join Date: Mar 2007
Location: Long Island, NY
Posts: 9,519
Default

Wind wash - soffit question?


Quote:
Originally Posted by BusterMN View Post
I am finishing an addition and i am wondering about the wind wash. Do i fill in the entire opening between the trusses, top to bottom and side to side? Or, do i leave a gap at the top so air can circulate between the soffit and the attic? If i leave a gap, how much of a gap do i leave?
What is "wind wash"?
Are you speaking of the soffit area under the roof?
What is the insulation and ventilation plan?
Soffit and ridge vents?
I'm not sure what you're referring to.
Ron

Ron6519 is offline   Reply With Quote
Old 04-23-2011, 08:18 AM   #3
mem
Member
 
Join Date: Dec 2010
Location: Central Ohio
Posts: 224
Default

Wind wash - soffit question?


Ron, I believe "wind wash" in this situation refers to the incoming soffit air pushing around the blown in insulation. If I'm correct then, Buster, you need to install the appropriate baffles between the rafters. They are cheap and easy to install. The incoming air thru the soffits needs an unobstructed path to the exhaust vents, be they mushroom vents, gable vents or, ideally, a ridge vent.
mem is offline   Reply With Quote
Old 04-23-2011, 08:29 AM   #4
Member
 
Join Date: Mar 2007
Location: Long Island, NY
Posts: 9,519
Default

Wind wash - soffit question?


If that's the case, when the soffit area is closed in properly, this will disappear.
Ron
Ron6519 is offline   Reply With Quote
Old 04-23-2011, 02:26 PM   #5
Newbie
 
Join Date: Apr 2011
Posts: 12
Default

Wind wash - soffit question?


Ok I had my signals crossed & my terms wrong. I meant something that applies to an uninsulated garage. I wasnt sure about the open end of the trusses that lead into the soffit on the house addition. I thought that had to be closed off by putting plywood in between the trusses at the top of the top plate. So I guess what I do is put those cardboard baffles in between the trusses from the top plate up. The insulation will be closed cell foam on the underside of the baffles so that there will be a gap for air to circulate from the soffit to the underside of the roof. I hope that makes sense. Thanks for the direction, it made me stop and think. Am I on the right track?







i
BusterMN is offline   Reply With Quote
Old 04-23-2011, 02:58 PM   #6
Member
 
Join Date: Mar 2007
Location: Long Island, NY
Posts: 9,519
Default

Wind wash - soffit question?


Quote:
Originally Posted by BusterMN View Post
Ok I had my signals crossed & my terms wrong. I meant something that applies to an uninsulated garage. I wasnt sure about the open end of the trusses that lead into the soffit on the house addition. I thought that had to be closed off by putting plywood in between the trusses at the top of the top plate. So I guess what I do is put those cardboard baffles in between the trusses from the top plate up. The insulation will be closed cell foam on the underside of the baffles so that there will be a gap for air to circulate from the soffit to the underside of the roof. I hope that makes sense. Thanks for the direction, it made me stop and think. Am I on the right track?
i
If you're using closed cell foam, you don't need to have an air space up the roof line, you would spray the foam directly to the sheathing.
Could you post a photo or 2 of this?
Ron
Ron6519 is offline   Reply With Quote
Old 04-23-2011, 03:53 PM   #7
Newbie
 
Join Date: Apr 2011
Posts: 12
Default

Wind wash - soffit question?


It will be a couple weeks before they come to spray the foam but i will post a couple pics when they do it. There seems to be some debate around here whether or not spraying the foam to the underside of the roof decking is good or bad. Even amongst the guys that do the foam. The shingle manufacturers wont warranty shingles overheating due to no air space for the underside to breathe. So I have been told. I recently found out that people foam the attic space so I don't have a lot of info on the directly to the decking way of doing it. The foam guy said that 75% will want the baffles sprayed so the attic has air and 25% want the decking sprayed. I'm not aware of any long term study of it going either way. I was just going with the baffle way to be safe.
BusterMN is offline   Reply With Quote
Old 04-23-2011, 11:16 PM   #8
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Wind wash - soffit question?


Need more information. Is it a cathedral ceiling in a house? Or an attic with a pitched roof above? Or the soffit of the house? Or house rafters exposed to a fire in a garage?

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 04-23-2011, 11:42 PM   #9
Newbie
 
Join Date: Apr 2011
Posts: 12
Default

Wind wash - soffit question?


Gary
Its a new heated house addition with 3.75/12 pitch common gable trusses. No attic to speak of due to the pitch. The soffit will be 20".
BusterMN is offline   Reply With Quote
Old 04-24-2011, 10:03 AM   #10
mem
Member
 
Join Date: Dec 2010
Location: Central Ohio
Posts: 224
Default

Wind wash - soffit question?


I'm sure Gary will correct me if I'm misinformed, but with proper air sealing and adequate insulation between the rafters, I don't believe there is a need for ventilation.

If you're set on using the baffles with ridge and soffit vents there should be no problem using the closed cell SPF on the underside of the baffles. A side benefit to this approach would make decking replacement in the future, if ever necessary, far easier.
mem is offline   Reply With Quote
Old 04-25-2011, 12:32 AM   #11
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Wind wash - soffit question?


Air seal first, as mem said, that is almost more important than insulation in an attic.http://www.familyhandyman.com/DIY-Pr...s/Step-By-Step

Many B.D. require attic venting rather than a conditioned attic. When heating/cooling mech.s are up there, it pays to condition it. With a low slope you want 2" to vent it. Use the baffles, add blocking to keep the SPF out of the soffits. Keep blocking/plywood, etc. on outside of wall plates to get full insulation over the wall. I'd use the Depot's baffle with the wind-wash blocker built-in and 35% more air flow than Lowe's foam one that may crush under the foam pressure and buy the w.b. separately;http://www.bergerbuildingproducts.co...sAccuvent.html

http://www.adoproducts.com/duro.html http://www.adoproducts.com/wind.html

Be sure to figure the venting;http://www.airvent.com/homeowner/pro...it-specs.shtml

Install the continuous venting close to the fascia, not the house for best pressure in the soffits. Use ridge or static vents up high for exhaust, last resort= gable vents.. Are you using SPF in the walls? Where are you located?

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 04-26-2011, 01:31 AM   #12
Newbie
 
Join Date: Apr 2011
Posts: 12
Default

Wind wash - soffit question?


Im in west central MN where the winters are harsh. I posted a ? on the roofing forum about ridge vents and some said go with a low pitch snow blocker ridge vent and some said dont use a ridge vent on a 3.75/12 pitch. The MN winter winds can darn near blow snow through a block wall so im still on the fence about the whole roof venting issue. I am getting the walls done in foam as well. That baffle with the wind wash blocker, does that block the space between the trusses and from the top plate to the roof decking? I thought i needed to keep that space open so the air wood circulate from the soffits to the roof or ridge vents? I assumed the baffle would be tight to the top plate then go up the pitch of the trusses. Then the air would circulate from the soffit to the ridge vent between the top of the foamed baffle and the roof decking. Does it sound like im thinking right on this deal?

Thanks for all the input.
BusterMN is offline   Reply With Quote
Old 04-26-2011, 07:31 AM   #13
mem
Member
 
Join Date: Dec 2010
Location: Central Ohio
Posts: 224
Default

Wind wash - soffit question?


As you can see, it does keep the ventilation path open from eave to ridge and allows for insulation directly above the top plate.

Name:  Accuvent.jpg
Views: 946
Size:  36.7 KB

Just staple it to the top plate, bend it as shown and attach it to your new 2x2 furring. What's your insulation requirements in MN? Even the best foam will only yield about R7 I think, which is great but I suspect you'll need 6 or 7 inches of it in the roof to be adequate.

mem is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Soffit Vents Atskodinski Building & Construction 6 03-05-2011 12:19 PM
Basement Fireblocking within HVAC Soffit ssmith147 Building & Construction 3 12-31-2009 06:36 AM
Dropped soffit over shower? StevePax Remodeling 2 12-24-2009 11:24 AM
soffit question nomoney Roofing/Siding 8 05-30-2006 11:57 AM
Soffit installation question milano Roofing/Siding 4 02-04-2006 10:13 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.