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Discussion Starter #1
I am wondering what the best way to attach the 6mil poly to my basement wall, I know putting holes can defeat the purpose of the barrier, from what I saw when I had to demo the basement.
 

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Tileguy
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I don't think you wanna do that, that would be a very bad thing. I recommend more research.

Jaz
 

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Tileguy
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Solarito said:
It is required by code. Need to have vapor barrier between foundation wall and studs
WOW, I'm pretty sure it's not a recommended procedure anymore, (here anyway). The plastic can create a moisture problem behind the wall and you may end up with a science experiment. However, you gotta go by the local code/custom, unless you find a better way and convince the inspector. Will they allow styrofoam panels glued to the wall? Some areas allow unfaced insulation, but panel are better cuz they're not affected by moisture.

Jaz
 

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Preferred method is to use 1.5 or 2 inch closed cell styrofoam. Use adhesive to concrete. Tape joints. Then 2x4 wall with r12 and no poly.
 

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Discussion Starter #7
Here is what the local code and guidelines show for my town:

http://www.perinton.org/Data/Documents/Basement Remodel 1-2011.pdf

I have came to the conclusion that there is no "right" way to finish a basement and it is best not to finish it at all. I have read so many different scientific articles that seem to contradict each other. I would consider using rigid foam insulation, though that is not allowed in my case.

My basement was finished prior and I removed it as it wasn't done properly. Most of the basement was fine, though I still demoed it to prevent future problems. A couple mistakes the previous guy did:

1) Fastened untreated furring strips to to the wall penetrating the vapor barrier. This caused moister through the barrier.
2) Didn't install vapor barrier properly. He left the barrier so it could collect water, which rotted one of the furring strips in a corner.
3) He installed a block window below grade w/o a window well. This caused the main problem with the mold and allow water to leak into basement behind the drywall. The holes in the vapor barrier allowed the moister through.
4) Lack of dehumidifier, partially my fault. Previous owner didn't have one now I have two that maintain a ~49% relative humidity in my basement. Now I have two.

Things I noticed:
1) There was no mold at ALL between the vapor barrier and the foundation wall.

Things I will do differently:

1) Attach vapor barrier correctly, need to figure out a way, maybe my only way is with some fasteners above the grade? <=this is why I posted this thread
2) use PT floor plate attached to the slab and not the foundation wall.
3) use unfaced rolled insulation

As the code requires a 6mil poly vapor barrier and my decade scientific experiment displayed no mold between exterior wall and vapor barrier, I will had to go on what I know. There will be gap between the vapor barrier and the interior wall.

Mold only occurred in the following areas:
1) Big area where the window was installed below grade
2) Area that of crumpled up poly that allow the collection of moister
3) Some areas where furring strips penetrate vapor barrier
 

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Tileguy
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What would have happened to the moisture if it hadn't entered the living area because the VB has holes in it? I think it has to evaporate into the warm side otherwise you'll trap it and droplets will end up near the floor and mold. Maybe not? It all depends on how tight everything is and of course how much moisture is present.

As for insulation, yes sure, it has to be unfaced, but remember, I'm a tile guy not a residential environmental expert.

If you have a damp basement, consider on of those air circulation systems that suck air out of the basement. Dehumidifiers do what they say, but they just recirculate the same air over and over.

Jaz
 

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Discussion Starter #9
What would have happened to the moisture if it hadn't entered the living area because the VB has holes in it? I think it has to evaporate into the warm side otherwise you'll trap it and droplets will end up near the floor and mold. Maybe not? It all depends on how tight everything is and of course how much moisture is present.

As for insulation, yes sure, it has to be unfaced, but remember, I'm a tile guy not a residential environmental expert.

If you have a damp basement, consider on of those air circulation systems that suck air out of the basement. Dehumidifiers do what they say, but they just recirculate the same air over and over.

Jaz
I neglected to say I have a floating slab w/ a perimeter drain system. Any excess would rain into that.
 

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Do a search for building science. They have a good article which discusses five different ways to insulate a basement with scientific evaluation of each. None of the five recommend a absolute vapor barrier-That is something like plastic with zero permeability. All articles I have ever read especially don't recommend fiberglass against poly. The building science article suggested the best was about 3 to 4 inches of XPS and polyiso against the block wall with furring strips and sheet rock on top of that. The theory was the board imsulation didn't allow water vapor from heat side to migrate to the cold block wall and condense out.

Thanks
JM
 

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Discussion Starter #11
Despite the recommendations, which I appreciate. If I were to hang 6mil poly, which would be the least worst way to do it?
 

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apply a thick bead ( at least 1/2 inch) of accoustic sealant to the perimeter of the wall, except the bottom. At the top, place the bead on the wall 3 inches below the top.

Let the caulking set up for a couple hours. do nothing.

then, roll out and cut your poly the length of the wall-unfolded- then apply red sheathing tuck tape to the top of the poly so that the tuck tape is onto the poly only half the width of the tape-so the tape is exposed and ready to be pushed to the top of the wall to help hold the poly in place- start in one of the upper corners, pushing the poly into the sealant so that the poly is glued to the sealant and the tuck tape is pressed very firmly into the top of the wall. ensure the poly is flat and glass-like when applied.

pressing very firmly at the top as you move along both on the tuck tape and where the poly meets the caulking is critical.

after the poly is attached to the three sides, then apply the accoustic to the floor at the bottom in the corner at the wall, pushing the poly into the corner tight. You may want to trim the poly that remains laying on the floor, but make sure to leave at least 4 inches laying on the floor beyond the caulked corner of the bottom of the wall.

done.
 
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