Vapor Barrier - Building & Construction - DIY Chatroom Home Improvement Forum

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


Thread Tools Display Modes
Old 03-06-2013, 09:47 AM   #1
Join Date: Mar 2012
Posts: 12
Rewards Points: 10

Vapor barrier

Did I need to put a vapor barrier over my insulation prior to putting up the Sheetrock? I have never installed a plastic before but now I am seeing this in different places and I am wondering what everybody thinks? There is no evidence of water in this basement. What is the point?


brucem is offline   Reply With Quote
Old 03-06-2013, 10:07 AM   #2
Join Date: Nov 2011
Location: Hartfield VA
Posts: 30,249
Rewards Points: 5,604

Vapor barrier

#1 Go back and add your location to your profile, very important that you do.
Just go up to quick links and edit info.
The point is your going to have warm moist air in the room hitting a cold moist wall and condencing without one.


joecaption is online now   Reply With Quote
Old 03-06-2013, 08:23 PM   #3
Registered User
Join Date: Mar 2009
Posts: 10,725
Rewards Points: 3,516

Vapor barrier

As Joe said, where are you located?

If any ads are present below my answer or words underlined/colored, I do not condone/support/use the product or services listed/linked to, they are there without my consent.
WELCOME to the forums, if I forgot to say it!
Gary in WA is offline   Reply With Quote
The Following User Says Thank You to Gary in WA For This Useful Post:
jaydevries (03-06-2013)
Old 03-06-2013, 08:32 PM   #4
Davejss's Avatar
Join Date: May 2012
Location: Northern Massachusetts
Posts: 574
Rewards Points: 702

Vapor barrier

Yes, you need a vapor barrior. Warm, moist air will travel through your wall where it cools and condenses. Check the codes in your area for thickness requirements, I.E. 4mill, 6 mill, etc.
Davejss is offline   Reply With Quote
Old 03-06-2013, 09:10 PM   #5
Join Date: Oct 2012
Location: Maryland
Posts: 3,679
Rewards Points: 2,116

Vapor barrier

I think its really funny when people say yes you need a vapor barrier, and tell someone where to put it without even knowing the parameters.

I learned a long time ago in the commercial roofing business that

1. There is no perfect vapor barrier, only vapor retarders.

2. When in doubt, leave it out.

Vapor pressure moves from warm moist to cold, and the rule of thumb is to have the dew point fall in the middle of the insulation, so you dont have hot moist air hitting a cold surface, like a glass of ice water on a hot humid day.

Putting a vapor retarder in the wrong place can result in "Pumping Up" the system in question with water because it cant escape when conditions reverse, like when you turn on the air conditioning. Thats why the rule of thumb is No. 2 Above. Unless tthe conditions remain the same at all times.
" A lot of men build things, and a lot of things fall down "

jagans is offline   Reply With Quote

Thread Tools
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

Top of Page | View New Posts