Tyveck For Vapor Barrier? - Insulation - Contractor Talk

Tyveck For Vapor Barrier?

 
Thread Tools Search this Thread Display Modes
Old 02-20-2010, 07:55 PM   #1
Plumber / Carpenter
 
Bill's Avatar
 
Trade: Virginia Building and plumbing contractor
Join Date: Mar 2006
Location: Farmville, Va
Posts: 1,652
Rewards Points: 1,014

Tyveck For Vapor Barrier?


Our building inspector told me that its much better to use tyveck than plastic for a vapor barrier when using uncrafted insulation.

Any thoughts?
__________________
Is it beer thirty yet
Virginia Department of Licensing
Virginia Plumbing Codes
Bill 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!

   

Advertisement

 

Old 02-20-2010, 08:13 PM   #2
Pro
 
katoman's Avatar
 
Trade: carpenter
Join Date: Apr 2009
Location: Kirkfield,Ontario, Canada
Posts: 6,102
Rewards Points: 2,000

Re: Tyveck For Vapor Barrier?


Tyvek is different that Typar. Tyvek allows air to pass through in both directions. It is not a vapour barrier. I've never heard of it being used inside a home.

It is intended for exterior as a wind barrier.

I'm not familiar with the insulation you stated. If it is figergass, then we use an appoved 6 mill poly VB

Advertisement

katoman is offline  
Old 02-20-2010, 09:26 PM   #3
Best looking Carpenter
 
forsmant's Avatar
 
Trade: General Contracting, Remodeling
Join Date: Dec 2008
Location: Omaha, NE
Posts: 179
Rewards Points: 133

Re: Tyveck For Vapor Barrier?


Tyvek has a 58 perm rating and 6 mil poly has a .06 perm rating. In order to have a vapor barrier the perm rating needs to be below 1.
forsmant is offline  
The Following User Says Thank You to forsmant For This Useful Post:
Tom Struble (02-21-2010)
Sponsored Links
Advertisement
 
Old 02-20-2010, 10:11 PM   #4
LRG WoodCrafting

 
Leo G's Avatar
 
Trade: Maker of Fine Sawdust
Join Date: May 2005
Location: Windsor Locks, Connecticut
Posts: 39,901
Rewards Points: 9,607

Re: Tyveck For Vapor Barrier?


Looks like your BI needs to read up on Tyvek a bit.
__________________
Sawdust Follows Me Everywhere
I can explain it to you, but I can't understand it for you.
Sanding is the bane of my existence
WWG1WGA

Quote:
Originally Posted by HusqyPro View Post
Carpenter by day.
Mad scientist by night.
http://lrgwood.com
Custom Cabinets in Hartford County Connecticut
Leo G is online now  
Old 02-20-2010, 10:16 PM   #5
Plumber / Carpenter
 
Bill's Avatar
 
Trade: Virginia Building and plumbing contractor
Join Date: Mar 2006
Location: Farmville, Va
Posts: 1,652
Rewards Points: 1,014

Re: Tyveck For Vapor Barrier?


Thanks. I thought it to be strange.
__________________
Is it beer thirty yet
Virginia Department of Licensing
Virginia Plumbing Codes
Bill is offline  
Old 02-21-2010, 08:17 AM   #6
Pro
 
buddy110's Avatar
 
Trade: Exteriors as a whole
Join Date: Oct 2009
Location: Hudson Valley NY
Posts: 1,379
Rewards Points: 530

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by forsmant View Post
Tyvek has a 58 perm rating and 6 mil poly has a .06 perm rating. In order to have a vapor barrier the perm rating needs to be below 1.

It's interesting. I'm having a few conversations with some pro's about perms, dense foam and tyvek. It seems the majority of pros, when using a foam AND tyvek, like to install foam first then tyvek afterwards. Dense foam has a perm rating of .01, Tyvek 58. Installing dense foam against the sheathing would therefore block vapor from escaping the house, trapping that moisture against the sheathing.

Now someone just told me tyvek will perm in both directions?? I was under the assumption it was a one way ticket. Can anyone comment?
buddy110 is offline  
Old 02-21-2010, 08:27 AM   #7
Plumber / Carpenter
 
Bill's Avatar
 
Trade: Virginia Building and plumbing contractor
Join Date: Mar 2006
Location: Farmville, Va
Posts: 1,652
Rewards Points: 1,014

Re: Tyveck For Vapor Barrier?


Maybe I need to re state my post.

The building inspector said when installing uncrafted insulation it is best to use tyveck INSIDE the house as a vapor barrier instead of plastic or paper between the drywall and insulation.
__________________
Is it beer thirty yet
Virginia Department of Licensing
Virginia Plumbing Codes
Bill is offline  
Old 02-21-2010, 08:31 AM   #8
Pro
 
Tom Struble's Avatar
 
Trade: siding
Join Date: Mar 2007
Location: west milford n.j.
Posts: 17,271
Rewards Points: 20

Re: Tyveck For Vapor Barrier?


in a properly assembled wall,where is this ''vapor'' coming from?
What use is tyveks fairly high permiability if you cover it with
a lower perm matierial?
__________________
Tom
Tom Struble is offline  
Old 02-21-2010, 08:35 AM   #9
Pro
 
buddy110's Avatar
 
Trade: Exteriors as a whole
Join Date: Oct 2009
Location: Hudson Valley NY
Posts: 1,379
Rewards Points: 530

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by tomstruble View Post
in a properly assembled wall,where is this ''vapor'' coming from?
What use is tyveks fairly high permiability if you cover it with
a lower perm matierial?


So by that theory why put dense foam at all?? (which has always been my feeling anyway) Putting it on top of tyvek virtually nullify's it's effect.
buddy110 is offline  
Old 02-21-2010, 09:11 AM   #10
Pro
 
Tom Struble's Avatar
 
Trade: siding
Join Date: Mar 2007
Location: west milford n.j.
Posts: 17,271
Rewards Points: 20

Re: Tyveck For Vapor Barrier?


i don't know
__________________
Tom
Tom Struble is offline  
Old 02-21-2010, 10:04 AM   #11
Pro
 
Tom Struble's Avatar
 
Trade: siding
Join Date: Mar 2007
Location: west milford n.j.
Posts: 17,271
Rewards Points: 20

Re: Tyveck For Vapor Barrier?


the problem i have with foam is that when you cut it around windows and put it over step flashing's is that you are screwing up the drainage plane
you should consider the foam installed this way a solid siding so installing the foam on a rain screen would probably be best for moisture control,not sure exactly what that does to its insulation qualities tho

best way to do it IMO is to install the foam first,pack out the openings the foam thickness,install roof step flashing on top of the foam,this way the drainage plane is directly under the siding where it should be,not 2 inches under
doing it this way you could probably just tape the seams/flashing's and forget the tyvek,i think i would still use i tho
__________________
Tom
Tom Struble is offline  
Old 02-21-2010, 10:12 AM   #12
Best looking Carpenter
 
forsmant's Avatar
 
Trade: General Contracting, Remodeling
Join Date: Dec 2008
Location: Omaha, NE
Posts: 179
Rewards Points: 133

Re: Tyveck For Vapor Barrier?


I don't think permeability is ever going to be a one way phenomenon.
forsmant is offline  
Old 02-21-2010, 10:20 AM   #13
Pro
 
buddy110's Avatar
 
Trade: Exteriors as a whole
Join Date: Oct 2009
Location: Hudson Valley NY
Posts: 1,379
Rewards Points: 530

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by tomstruble View Post
the problem i have with foam is that when you cut it around windows and put it over step flashing's is that you are screwing up the drainage plane
you should consider the foam installed this way a solid siding so installing the foam on a rain screen would probably be best for moisture control,not sure exactly what that does to its insulation qualities tho

best way to do it IMO is to install the foam first,pack out the openings the foam thickness,install roof step flashing on top of the foam,this way the drainage plane is directly under the siding where it should be,not 2 inches under
doing it this way you could probably just tape the seams/flashing's and forget the tyvek,i think i would still use i tho

Ya, I'm beginning to see the logic behind this, especially knowingf the tyvek will perm back into the home.

To be honest, I think I'm going to resort to a permeable foam. It's just better all around.
buddy110 is offline  
Old 02-21-2010, 11:15 AM   #14
Pro
 
Tom Struble's Avatar
 
Trade: siding
Join Date: Mar 2007
Location: west milford n.j.
Posts: 17,271
Rewards Points: 20

Re: Tyveck For Vapor Barrier?


i think i agree and it would be nice if the back of the foam was sculpted to encourage drainage

to be honest i look at the tyvek that i install pretty much as a bulk water barrier,i detail it as much as i reasonably can but by the time I'm there the roofs and ledgers make getting an installation like is in the manual....well

to do that effectively is to build the walls on deck, then tyvek them, then
this way it would be everywhere it has to be

i think the main reason guys wanna do the tyvek first is that its easier to staple it on than having to use 2'' or whatever nails
__________________
Tom
Tom Struble is offline  
Old 02-21-2010, 11:46 AM   #15
Don
 
rotarex's Avatar
 
Trade: Renovator/ Builder
Join Date: Mar 2008
Location: Toronto
Posts: 1,322
Rewards Points: 508

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by Bill View Post
Maybe I need to re state my post.

The building inspector said when installing uncrafted insulation it is best to use tyveck INSIDE the house as a vapor barrier instead of plastic or paper between the drywall and insulation.

after i read the construction book, i wonder why we dont use tyveck also, but it wont meet code as vapor barrier in theory is suppose to work, for me it looks like it would build mold from all the water build up
__________________
Custom Decks
Custom aquarium all salt water
Renovation
next on my list............planting trees for all those material i used
rotarex is offline  
Old 02-21-2010, 12:17 PM   #16
Pro
 
MJW's Avatar
 
Trade: General Contractor, Roofing, siding, windows
Join Date: Jan 2006
Location: MN
Posts: 1,934
Rewards Points: 1,772

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by tomstruble View Post
in a properly assembled wall,where is this ''vapor'' coming from?
What use is tyveks fairly high permiability if you cover it with
a lower perm matierial?
Exactly, and I agree with you on the foam first then tyvek, if required, and the build out of flashings and windows.

Vapor barrier and it's placement depends on your climate and where the moisture is (inside or outside).

I have not totally figured this out yet, but getting close.
MJW is offline  
Old 02-21-2010, 12:18 PM   #17
Pro
 
MJW's Avatar
 
Trade: General Contractor, Roofing, siding, windows
Join Date: Jan 2006
Location: MN
Posts: 1,934
Rewards Points: 1,772

Re: Tyveck For Vapor Barrier?


Another thing to consider is the perm rating of the OSB, plywood, buildrite that is used. I'm not sure if I agree with totally sealing walls like we do up here in the north.
MJW is offline  
Old 02-21-2010, 12:37 PM   #18
KemoSabe
 
loneframer's Avatar
 
Trade: residential framing/siding/general carpentry
Join Date: Feb 2009
Location: Vineland, New Jersey
Posts: 14,233
Rewards Points: 12,218

Re: Tyveck For Vapor Barrier?


Quote:
Originally Posted by MJW View Post
Another thing to consider is the perm rating of the OSB, plywood, buildrite that is used. I'm not sure if I agree with totally sealing walls like we do up here in the north.
I agree. OSB and CDX both have low permeability. However, with a proper vapor barrier on the inside (warm in winter), most of the moisture would be occuring from the outside, whether by improper flashing details or moisture being driven through the WRB in the wrong direction. With a non permeable foam, any moisture that accumulates behind it wil be trapped and wreak havok. I still prefer the variable permeability of #30 felt over plastic wraps of any kind.
__________________
__________________________________




"Walking the fine line between production and perfection"




__________________________________
loneframer is offline  
Old 02-21-2010, 12:42 PM   #19
Pro
 
Tom Struble's Avatar
 
Trade: siding
Join Date: Mar 2007
Location: west milford n.j.
Posts: 17,271
Rewards Points: 20

Re: Tyveck For Vapor Barrier?


yea but i thought you didn't like to combine the two?And if ya think about it Lone maybe 2 layers of felt is a good idea under any siding not just stucco for the same ''wrinkly'' effect
__________________
Tom
Tom Struble is offline  
Old 02-21-2010, 12:42 PM   #20
Rory Read
 
Rory Read's Avatar
 
Trade: Basements, Excavation, Waterproofing and Finishing
Join Date: Feb 2010
Location: Portland, OR
Posts: 29
Rewards Points: 25

Re: Tyveck For Vapor Barrier?


No matter where you live, you want the wall to breathe in at least one direction or the other. You have to figure what makes sense for your climate. After you decide that, then you decide where vapor barriers and retarders go and what your ideal wall construction looks like.

Try the DOE for regional guidance:

http://www1.eere.energy.gov/building...lications.html

Advertisement


Last edited by Rory Read; 02-21-2010 at 12:43 PM. Reason: can't type
Rory Read 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


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?