# PVA Primer as a vapor barrier



## Brushjockey (Mar 8, 2011)

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 (Dec 23, 2007)

Brushjockey said:


> 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 (Dec 12, 2010)

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


----------



## Brushjockey (Mar 8, 2011)

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 (Oct 26, 2011)

Nailbags said:


> 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 (Jan 30, 2011)

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


----------



## chrisn (Dec 23, 2007)

jsheridan said:


> 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 (Nov 10, 2011)

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/file/pdfs/95-500TDS.pdf

Good luck with that!


----------



## jsheridan (Jan 30, 2011)

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 (Mar 8, 2011)

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


----------



## Gary in WA (Mar 11, 2009)

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_home/insulation_airsealing/index.cfm/mytopic=11810
Never in a basement.
 http://www.buildingscience.com/documents/published-articles/pa-built-wrong-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 (Feb 1, 2012)

GBR in WA said:


> 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_home/insulation_airsealing/index.cfm/mytopic=11810
> Never in a basement.
> ...


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 (Dec 23, 2007)

jsheridan said:


> 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 (Jan 30, 2011)

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


----------



## Matthewt1970 (Sep 16, 2008)

You should never try and rely on paint for a vapor barrier. If you get a crack in a corner or along the floor line or ceiling, bye bye vapor barrier.


----------



## Brushjockey (Mar 8, 2011)

I think the HO actually had no idea what they were asking for, or why. 
And Nail hasn't been back to clarify.
And the county has it wrong. But that's gov't work for ya.


----------



## Gary in WA (Mar 11, 2009)

WA State has own Energy Code. Walls require interior (warm side) vapor retarder or X" exterior foamboard. Sounds like the OP didn't use the paper-faced insulation and needed/found an acceptable replacement- post #13. 

Vapor barriers (area weighed) can have holes, air barriers cannot; http://www.greenbuildingadvisor.com...ier-or-vapor-barrier-building-science-podcast

Gary


----------



## Nailbags (Feb 1, 2012)

GBR in WA said:


> WA State has own Energy Code. Walls require interior (warm side) vapor retarder or X" exterior foamboard. Sounds like the OP didn't use the paper-faced insulation and needed/found an acceptable replacement- post #13.
> 
> Vapor barriers (area weighed) can have holes, air barriers cannot; http://www.greenbuildingadvisor.com...ier-or-vapor-barrier-building-science-podcast
> 
> Gary


The home owner did their own insulation. And as such I asked him about it but he told me the inspector said to use PVA primer on the dry wall and all would be good. That is Code for Washington state. two coats


----------



## Gary in WA (Mar 11, 2009)

LOL, I was answering post #17 and 16, stating to read your post number 13...... Sorry, I should have said the OP's *homeowner *needed a vapor retarder as is stated in #13.
Sounds as if you are a neighbor of mine, you'll like these, Nailbags;

http://www.energy.wsu.edu/Documents/2009 WSEC Chapters 1-10.pdf

https://docs.google.com/viewer?a=v&...elqlWo&sig=AHIEtbSxbpccOD8imQaYB0OzT5oKmAygdg

http://www.dsireusa.org/incentives/index.cfm?getRE=1?re=undefined&ee=1&spv=0&st=0&srp=1&state=WA

Gary


----------

