# Damp drywall due to improper vapor barrier install?



## joecaption (Nov 30, 2011)

Got any pictures?
Happen to be below a window or beside the door?
Got ice dams on the roof?


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## Spacemoose (Feb 9, 2014)

Theres no ice dams on the roof and there is a window about 5ft away on one side (the side with the duct tape), but no window on the other side but the drywall is still soft along the bottom.


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## SPS-1 (Oct 21, 2008)

Is this above grade, basement, or where?

Have you had carpet in this area? Sometimes the outside edge of the carpet (against an exterior wall) will be dirty. This is due to a leaky sill plate, and air constantly blowing in and out.


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## Spacemoose (Feb 9, 2014)

Its above grade and the laminate was installed before I moved in (I took possession last July). Both walls are exterior walls.


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## ThatDaveGuy (Dec 31, 2010)

I would think that if you had serious moisture issues in there you'd see it on the wood, doesn't look too bad. Fiberglass looks stuffed, minimal, maybe you had condensation on the backside of the drywall itself due to poor insulation?


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## joecaption (Nov 30, 2011)

Please post a picture of the outside in that area.
Another guess that may have caused it is the outside sheathing and or siding was not installed below the sill plate so cold airs leaking in and when it hits the back side of the warmed plastic it's condensing.


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## danpik (Sep 11, 2011)

If you are truly getting condensation forming in that area, and it is possible, it will be from a cold spot forming in the wall due to improper insulation. A poor insulation job such as a small gap, thin insulation, or too tightly compacted will cause a cold spot. Warm moist air from inside the house will condensate on the cold surface and over time will weaken and deteriorate the drywall. 

The vapor barrier between the drywall and insulation, if properly installed, will prevent the moisture from saturating the insulation. However, it will not stop the formation of condensation if there is a gap between the insulation and vapor barrier. The insulation, if properly installed, should be tight against the vapor barrier to prevent any cold spots from forming.

Duct tape also should not be used in this application as over time it will dry out. There are specific products to use to seal vapor barriers in case of gaps or cuts.


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## Spacemoose (Feb 9, 2014)

There was a small bit of frost on the outside of the vapor barrier this morning. By the age of the house I could easily see that the insulation would be sub standard.

Heres the outside. Theres a few small cracks in the stucco but nothing major. If it warms up (its currently -24C/-11F) I could try to run a small bead of silicone between the stucco and concrete.


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## Spacemoose (Feb 9, 2014)

I think my plan of attack is going to be: 

-Buy some sheathing tape, some poly, and possibly a tube of acoutic sealant to fix the small holes and seal the corner. 

-Patch the hole in the drywall

-Wait a few days and see if the drywall gets soft

-Run some foam weatherstripping/backer rod in the gap between the laminate and the drywall along the walls.


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## ToolSeeker (Sep 19, 2012)

Does this drywall run all the way to the floor? It looks like it on the left. If it does this could just be water from mopping the floor. That is why we always cut the drywall 1/2" up from the floor. Drywall is very pours and will wick water like crazy.


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## Spacemoose (Feb 9, 2014)

It does run all the way to the floor but we haven't mopped that area anytime recently.


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## ToolSeeker (Sep 19, 2012)

What about previous owners? Once drywall gets wet and crumbly it rarely goes back to its original condition. The reason I bring this up is I really don't see any thing wrong with the insulation or barrier.


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## Gary in WA (Mar 11, 2009)

Is the floor concrete? For drywall to "get soft" will take more than a few days. IF wood frame floor, is the floor insulated? Vapor barrier on the dirt? Ventilated crawl-space? Is the wall VB taped to floor in picture? Was there a couch in front of wall there to restrict air circulation? The drywall nails are pretty rusted.... did you check various locations with a moisture meter ($25)?

Gary
PS. don't caulk/seal the stucco/parging joint or it won't drain if weeps were used...welcome to the forums!


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## cleveman (Dec 17, 2011)

I currently live in a home built in 1970.

I got into a wall while renovating the bathroom and was expecting to find R-11 insulation. To my surprise, I found R-7.5, which I didn't know had ever been offered.

When it is cold, I will get some frosty spots in corners and beside the exterior door.

I attribute this to the thin insulation, and it is quite possibly installed poorly, plus I like to keep the humidity high even when it is too cold outside.

You might want to see what you have there for insulation.

My solution is to one day re-insulate.


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## 26yrsinflooring (Jul 1, 2008)

*Stucco....*

You are in Canada and they put stucco on....What is behind the stucco?


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## Spacemoose (Feb 9, 2014)

So after some more poking around the drywall (freshly painted) came off. The moisture was due to poor vapor barrier and insulation. What I found was not promising (it could have been a lot worse though).
The vapor barrier is/was 2mil secured with maybe a dozen staples along the top and loosely draped down. The electrical box was not sealed in any way, just a big gaping hole around it an the wall between the studs was covered in frost. I then tore out the drywall in the closet (also freshly painted) and discovered more of the same. I now have all the drywall, insulation, and vapor barrier on that wall removed and a handfull of lamps and fan going to dry it out. 

I did a home depot run earlier today and bought some Roxul R14 insualtion batts, some more sheathing tape, some 6 mil poly, and some other random stuff. With any luck itll be dry enough tonight to re insulate, and tomorrow I can tear out the other wall and do the same.

Next week/weekend Ill be tearing down the master bedroom walls and doing the same. There will be just as bad if not worse.


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## Spacemoose (Feb 9, 2014)

So I purchased a moisture meter and tested various areas of the wall. It ranged anywhere from 9% -17% (23 was the highest but the wood was still visibly moist). I also gave the walls a quick misting of anti mold spray (http://www.homedepot.ca/product/946-ml-concrobium-mold-control-trigger-spray-bottle/949056) for good measure. I also have a few fans and a dehumidifier running as well. 

At what moisture level should I be safe to start re insulating the walls? Only smalls sections are reading 17% and higher.


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## cleveman (Dec 17, 2011)

I think you are ready to go. The wall will be drying to the outside anyway.


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## Windows on Wash (Aug 30, 2011)

Caulk and sealant are your friend here.

Airtight Drywall Approach (ADA).


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## Spacemoose (Feb 9, 2014)

First room is re-insulated and almost vapor barrier-ed. I ran out of sealant last night, I went a wee bit excessive on one wall. Started ripping the walls out of the master bedroom to check for moisture and luckily there was little to nothing. Theres were signs of dripping condensation on the wall. Aslo, this is how the outlets were "sealed".


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## Spacemoose (Feb 9, 2014)

Heres one wall. And, with all the excess sealant on the studs the drywall screw should be sealed as well.


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## Windows on Wash (Aug 30, 2011)

Seal behind the outlet plates.

Google "putty pads"


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## 26yrsinflooring (Jul 1, 2008)

If you don't stop the moisture before the insulation you will get a greenhouse effect and the condensation will build on the inside of your vapor barrier and all you are doing will have little effect.
I am trying to wrap my head around the fact you stucco on your walls in Canada...
Stucco is neither moisture proof or vapor proof.
This was proven when they tried to use stucco in high humidity geographical areas.
It sounds to me like the problem is behind the stucco.
What is your average humidity ?


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## Spacemoose (Feb 9, 2014)

26yrsinflooring said:


> If you don't stop the moisture before the insulation you will get a greenhouse effect and the condensation will build on the inside of your vapor barrier and all you are doing will have little effect.
> I am trying to wrap my head around the fact you stucco on your walls in Canada...
> Stucco is neither moisture proof or vapor proof.
> This was proven when they tried to use stucco in high humidity geographical areas.
> ...


Im pretty sure the frost build up on the inside was just due to warm air condensing. The vapor barrier was extremely poorly done and the insulation averaged maybe 2 inches thick and was compressed in a lot of places. If my new stuff is R14 I would guess that the old stuff maybe rated R7. Some of the new vapor barrier and insulation has been up for about a day and there's no sign of moisture/frost on the inside or the outside.

Behind the stucco is most likely a layer or 2 of tar paper then plywood (which is where I had frost). The house is 47 years old and the stucco is doing pretty good, a few cracks here and there but nothing major.

The Relative Humidity averages 50% -75%


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## 26yrsinflooring (Jul 1, 2008)

Back in 1992 I did a lot of work for a casino riverboat in Lake Charles Louisiana.
They had these large buildings built on barges and they had brought their west coast ideas and stuccoed everything.
The stucco could not take the moisture and relative humidity of the Deep South, about 89%.

It could not take the rain either,within a few short months they had severe moisture problems. They then started claiming they had intended it to be temporary anyway.

I am looking at this on the opposite side of the spectrum, you have such extreme cold and your humidity is high compared to where stucco is so prominent , the west, and in my home state Arizona.
I just don't see how that stucco has held up for so many years.
I had a builder uncle that used to laugh about installing stucco, he was from the northwest and he said stucco would never last in Washington state, the reason he was laughing is his exterior finish cost were cut in half by using stucco in Arizona as compared to WA requirements.

I don't think your problem is solved, I hope what you do works but I fear the cold in the form of frost will keep condensing into the warm spot close to your drywall.
We call plastic sheeting a moisture blocker but it is not a a vapor barrier.


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## ToolSeeker (Sep 19, 2012)

Not sure I agree I live in Fla. not far from the Gulf and believe me we know about humidity and probably 95% of the homes here are stuccoed and we don't have have the problems you mentioned. When I lived in Ohio we had stuccoed houses although not near as many as down here.


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## 26yrsinflooring (Jul 1, 2008)

I know they have made improvements in stucco but not 47 year old stucco.

I would be curious to see what the walls behind the drywall looked like in your house. I assume if the proper vapor barriers are used or if you put stucco over block.... As many houses in Florida are you will not have problems.
However this fellow is' having problems so getting to the core of the issue is key.
Frost and moisture is getting into his interior walls, you can waterproofing the interior all day long but if you don't solve the moisture saturation coming in , any fix is temporary.

I was doing a flooring job for this Cajun builder that built a hurricane proof house.... Or so he thought, I think Ike took it out.
He had double plywood interior walls and double plywood exterior walls , the finish was brick. They would laugh and joke about how people are using stucco in high humidity areas not realizing that moisture will find a way in, you will not know it for years but one day it will show itself.

Here is another example, in Charleston SC there has been a flurry of lawsuits due to the use of stucco on exterior walls. They have had to shut down townhouse developments built in the 80s because they are rife with mildew.
You can hardly get financing on older town houses due to the fear of potential losses from moisture damage.


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## danpik (Sep 11, 2011)

Spacemoose said:


> *Im pretty sure the frost build up on the inside was just due to warm air condensing.* The vapor barrier was extremely poorly done and *the insulation averaged maybe 2 inches thick and was compressed in a lot of places*. If my new stuff is R14 I would guess that the old stuff maybe rated R7. Some of the new vapor barrier and insulation has been up for about a day and there's no sign of moisture/frost on the inside or the outside.
> 
> Behind the stucco is most likely a layer or 2 of tar paper then plywood (which is where I had frost). The house is 47 years old and the stucco is doing pretty good, a few cracks here and there but nothing major.
> 
> The Relative Humidity averages 50% -75%


It sounds like you solved the problem. The poor insulation was causing cold spots on the back of the drywall which was causing condensation to form on the wallboard. A good insulation job will not allow a cold air spot to form behind the wallboard. The vapor barrier will prevent the moist air from permeating thru to the insulation where it will saturate it and help cause cold spots. Wet insulation is not a good insulator and will conduct cold to the inside. Nice job on the repairs:thumbup:


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## 26yrsinflooring (Jul 1, 2008)

danpik said:


> It sounds like you solved the problem. The poor insulation was causing cold spots on the back of the drywall which was causing condensation to form on the wallboard. A good insulation job will not allow a cold air spot to form behind the wallboard. The vapor barrier will prevent the moist air from permeating thru to the insulation where it will saturate it and help cause cold spots. Wet insulation is not a good insulator and will conduct cold to the inside. Nice job on the repairs:thumbup:


It certainly looks well done from the pictures but I am a little uncertain about a few things: the vapor barrier is on the outside (inside of house) of the insulation how will that prevent moisture from getting to the insulation? 
That would indicate the moisture is coming from the inside of the house.
If the air flow is coming from the outside of the house due to the proof of frost on the plywood how does that prevent moisture from building in the insulation since it is between the plywood and interior vapor barrier?
Perhaps I misunderstood you.


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## Spacemoose (Feb 9, 2014)

The previously posted pictures show the plywood of the exterior wall. The warm air inside the house is quite a bit more humid then the cold air outside (even though the outside relitive humidity might be more, cold air holds less water). If I remember my grade school science correctly its like saying a large cup filled 50% of the way still holds more water then a small cup thats 90% filled.


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## danpik (Sep 11, 2011)

26yrsinflooring said:


> It certainly looks well done from the pictures but I am a little uncertain about a few things: the vapor barrier is on the outside (inside of house) of the insulation how will that prevent moisture from getting to the insulation?
> That would indicate the moisture is coming from the inside of the house.
> If the air flow is coming from the outside of the house due to the proof of frost on the plywood how does that prevent moisture from building in the insulation since it is between the plywood and interior vapor barrier?
> Perhaps I misunderstood you.


 So, where should the vapor barrier be?


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## 26yrsinflooring (Jul 1, 2008)

Well it is clear the owner of the problem has addressed it the best that an be done short of removing the stucco , which is not an option.

I am only a flooring and shower guy so blocking moisture and containing and redirecting water is a large part of my job. I am not a builder so the rules I will use will be different than a builders.
For proper moisture blocking you want a water and vapor proof barriers directly behind exterior layer that is being impacted by the moisture.

So in retrospect the moisture barrier should be on the outside of the plywood and installed with a non invasive procedure.
Tarpaper is not exactly the best method but it is acceptable if install properly, it normally is not installed in manner that will allow to be used to its full potential.
The seams are not taped and quite possibly are not overlapped correctly. Then the lathe is applied to accept the stucco, the application of the lathe compromises the whole aspect of installing a moisture barrier like tarpaper as it now become a pincushion with several hundred nails or staples hammered into it.

I can take short cuts in a shower although I choose not to, there are many short cuts with flooring and you can achieve an equal or even superior job.
There are no shortcuts when you are building walls on exterior houses in northern latitudes.
.... Now I mean there are shortcuts that can be taken but they will expose themselves in short time.


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## 26yrsinflooring (Jul 1, 2008)

I must say Mike Holmes has no problem with digging out from the foundations of the basements and applying the moisture barriers in the form of tar directly to the brick.
I applaud this method it is done correctly.
I find him to be a bit overbearing on some issues, well versed on many things and not so well versed on flooring and shower applications.


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