# Vapor barrier seal



## Jwinston (Jan 25, 2017)

Hello,


I have a question about basement vapor barrier. My home is 2 years old. Basement is pored concrete and the builder has insulated everything. A few days ago I noticed that the plastic membrane is not tightly attached at the floor, maybe the caulking sealant is coming off. I attached 2 pictures. My concern is, does the vapor barrier has to be air tight? is it even possible?  or is it normal to have some open areas?

Thank you,


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## kok328 (Jan 25, 2017)

should be air tight with taped seams.
if you have enough length, run a bead of silicone on the floor and press the flap into the silicon.


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## nealtw (Jan 25, 2017)

Jwinston said:


> Hello,
> 
> 
> I have a question about basement vapor barrier. My home is 2 years old. Basement is pored concrete and the builder has insulated everything. A few days ago I noticed that the plastic membrane is not tightly attached at the floor, maybe the caulking sealant is coming off. I attached 2 pictures. My concern is, does the vapor barrier has to be air tight? is it even possible?  or is it normal to have some open areas?
> ...



You must be in Canada?
Yes it should be completely sealed.


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## Jwinston (Jan 25, 2017)

Yes. I live in Canada. What kind of product can I use to seal the plastic at the bases? Is it some kind of caulking?  My one year Tarion is not over yet. Maybe this is something the builder can fix.


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## nealtw (Jan 25, 2017)

http://www.lepage.ca/en/lepage-products/sealant-construction-sealant/pl-sealant/vapour-sealant.html


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## kok328 (Jan 26, 2017)

Jwinston said:


> Yes. I live in Canada. What kind of product can I use to seal the plastic at the bases? Is it some kind of caulking?  My one year Tarion is not over yet. Maybe this is something the builder can fix.



Silicon or a product called Quad available at big box stores.


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## nealtw (Jan 26, 2017)

kok328 said:


> Silicon or a product called Quad available at big box stores.



The link I gave him is the stuff he has now, that's the normal up here.


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## Jwinston (Feb 17, 2017)

Thanks for the replies guys. Much appreciated


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## Jwinston (Mar 23, 2017)

Hello guys. Yesterday I noticed light condensation in the basement corner, right behind the base stud between the floor and the wall. What do you guys think? is thins a common occurrence? I took a pic behind the stud, right at the junction between the floor and the wall.


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## nealtw (Mar 23, 2017)

If you have air leaks that allow warm moist air to get behind the insulation and contact cold concrete you will get condensation.
Tape a square of sheet plastic to the the area in question. moisture on the surface of that plastic would be condensation, moisture on the backside would be coming thru the concrete.


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## slownsteady (Mar 23, 2017)

Following up on Neal's suggestion; you tape the square of plastic to the concrete wall. Tape all four sides.


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## Jwinston (Mar 23, 2017)

Thanks nealtw and slownsteady. The vapor does appear on the backside of the plastic. So it seems to come from the outside. Do you think that maybe I should open that area and let it dry out? Is this a common occurrence?


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## nealtw (Mar 23, 2017)

Jwinston said:


> Thanks nealtw and slownsteady. The vapor does appear on the backside of the plastic. So it seems to come from the outside. Do you think that maybe I should open that area and let it dry out? Is this a common occurrence?



Water does not usually leak thru solid concrete but it will wick thru it from cold to warm.


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## stadry (Oct 6, 2017)

*barrier tape's usually used by pro's - we buy ours on eBay*


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## nealtw (Oct 6, 2017)

stadry said:


> *barrier tape's usually used by pro's - we buy ours on eBay*



They seal almost anything up here with that black crap, but they use tape where it will stick.


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## stadry (Oct 9, 2017)

*on walls, we use nailed-on p/t'd 1x2's for termination strips*


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