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-   -   PVA Primer as a vapor barrier (http://www.diychatroom.com/f4/pva-primer-vapor-barrier-142448/)

Nailbags 05-02-2012 04:31 PM

PVA Primer as a vapor barrier
 
So I have a customer that after i finished their sheet rock wants me to do the painting for them I told them sure it will be time and materials that said. I went and bought the primer To lay down before I do the orange peel texture. Then shoot a second coat of primer over the the texture. I come back with it and he asks why not PVA primer it is cheaper and acts as vapor barrier. I have never heard such a thing i told him my time is money and If you want me to return the primer I will charge for my time and mileage. he was cool with that. But I told him I would pick up in the morning. So any pros out there with any insight as to the validity of his statement?

Brushjockey 05-02-2012 04:49 PM

PVA is barely a sheetrock primer- it is certainly not a vapor barrier.
I only know a few things ( besides hi test stuff) that I would call that. A coat of oil or a coat of Gardz come to mind.

chrisn 05-02-2012 04:52 PM

Quote:

Originally Posted by Brushjockey (Post 912923)
PVA is barely a sheetrock primer- it is certainly not a vapor barrier.
I only know a few things ( besides hi test stuff) that I would call that. A coat of oil or a coat of Gardz come to mind.


:thumbsup::yes:

Gymschu 05-02-2012 08:43 PM

Shouldn't the vapor barrier be on the other side of the wall?

Brushjockey 05-02-2012 09:21 PM

Yes- but it depends which direction you are trying to stop the vapor from coming from.
In a bath the paint side makes sense.

ric knows paint 05-03-2012 07:53 AM

Quote:

Originally Posted by Nailbags (Post 912910)
So I have a customer that after i finished their sheet rock wants me to do the painting for them I told them sure it will be time and materials that said. I went and bought the primer To lay down before I do the orange peel texture. Then shoot a second coat of primer over the the texture. I come back with it and he asks why not PVA primer it is cheaper and acts as vapor barrier. I have never heard such a thing i told him my time is money and If you want me to return the primer I will charge for my time and mileage. he was cool with that. But I told him I would pick up in the morning. So any pros out there with any insight as to the validity of his statement?

Hiya Nailbags...

Although most people here don't agree with me regarding PVA primers and their viability in the overall painting scheme, I think it'd be a really far stretch to suggest that any PVA could perform well as a vapor barrier, if at all...

But a better question might be why is a vapor barrier important to your customer? Actual vapor barriers makes sense for below grade walls, but if you've got issues above grade regarding moisture/vapors, there are far better, more effective, ways to deal with that type of problem...Years ago, I seem to remember Zinsser advertising that a vapor barrier could be created by using BullsEye 123 on outside walls, and BIN on inside walls. The problem with a system like that is if you have a moisture problem within your home, it's possibly the result of over-insulating - moisture must be able to escape your home, and if you block all paths of egress, this same moisture will reveal itself in some other form within your home such as fogged up windows, doors and windows that don't shut properly, nailhead popping & rusting on trim, mold/mildew growth, curious infestations of insects attracted to damp wood...did I mention mold/mildew growth? (...and all this is just to keep the moisture, inside the house, from escaping - a completely different set of problems exist if you're trying to keep outside moisture from coming in the home)

I realize I've illustrated kind of a worst-case, end of the world, scenario...but I have seen homes that were so over insulated that all these conditions were present...Care to guess who the homeowners tend to blame for these problems?

But, a PVA drywall primer as a vapor barrier? I don't think so...

jsheridan 05-03-2012 10:18 AM

To my knowledge, BIN is the least permeable paint/primer available.

chrisn 05-03-2012 03:43 PM

Quote:

Originally Posted by jsheridan (Post 913545)
To my knowledge, BIN is the least permeable paint/primer available.


I would bet Draw tite would be up there as would Gardz which was copied from DT

http://www.scotchpaint.com/drawtite.html

Mr. Paint 05-03-2012 04:40 PM

Nailbags: Vapor barriers were invented for commercial, sealed buildings with a controlled environment to protect the drywall and construction from the ambient moisture intruding. This is not an issue in a residence unless she grows mushrooms. I know you are in the Pacific Northwest and have access to this, if they insist:
http://www.kellymoore.com/userfiles/.../95-500TDS.pdf

Good luck with that! :)

jsheridan 05-03-2012 06:46 PM

I didn't know Gardz had vapor barrier quality. Maybe that's why, as a latex, it can be used to seal wallpaper adhesive as a barrier for latex finish. Learn something new everyday. I learned something new, and proved that I learned something on a previous day: wallpaper adhesive.

Brushjockey 05-03-2012 08:19 PM

Yup- all that. That's why we've been saying Gardz works instead of oil.

Gary in WA 05-03-2012 09:33 PM

I don't usually enter the "Paint" room, but the title caught my eye. He may have read where I sometime recommend a vapor barrier primer or paint on bath walls and certain ceilings with attics/ventilation above- without plastic sheeting.

http://www.energysavers.gov/your_hom.../mytopic=11810
Never in a basement.
http://www.buildingscience.com/docum...ong-from-start

Not all v.b.paint/primer ratings are the same- applied to drywall or film perm.rating; http://www.mde.com/publications/Jan07News.pdf

Gary

Nailbags 05-03-2012 10:03 PM

Quote:

Originally Posted by GBR in WA (Post 914005)
I don't usually enter the "Paint" room, but the title caught my eye. He may have read where I sometime recommend a vapor barrier primer or paint on bath walls and certain ceilings with attics/ventilation above- without plastic sheeting.

http://www.energysavers.gov/your_hom.../mytopic=11810
Never in a basement.
http://www.buildingscience.com/docum...ong-from-start

Not all v.b.paint/primer ratings are the same- applied to drywall or film perm.rating; http://www.mde.com/publications/Jan07News.pdf

Gary

Come to find out I went to my building dept to question and because he used non faced insulation PVA primer two coats are approved for a vapor barrier in The county I did the work in.

chrisn 05-04-2012 01:27 AM

Quote:

Originally Posted by jsheridan (Post 913874)
I didn't know Gardz had vapor barrier quality. Maybe that's why, as a latex, it can be used to seal wallpaper adhesive as a barrier for latex finish. Learn something new everyday. I learned something new, and proved that I learned something on a previous day: wallpaper adhesive.


:thumbsup::whistling2:

jsheridan 05-04-2012 06:03 AM

I'm slow, but I learn over time. :thumbsup:


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