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basement wall moisture proofing

2K views 3 replies 2 participants last post by  Ron6519 
#1 ·
Hello,

I'm new to the forum so not sure if this kind of situation has been discussed before. I didnt spot this in the FAQ, so here I go;

I am looking to insulate and finish the basement walls in our 50 year old home. The foundation walls are of cinder block and there is an interior water control system installed (weep holes in the blocks, drytrak drainage tile to catch the water coming in and flange around the perimeter and a sump pump). Any possible water coming inside the wall should run down and caught by the drain.

As far as understand the system is guaranteed to keep the floor dry but there is a chance the walls can still get damp. So far I haven't seen any obvious moisture but I have yet to experience spring thaw in this home. Before I insulate the walls, should I treat the walls with sealant or put a plastic or tar paper membrane between the wall and the framing/insulation, in addition of the normal vapor barrier on the warm side?

Thanks, Jari
 
#2 ·
You should be able to look at the walls and the floor for evidence of water. Do the walls have any efflorescence? Are there water stains on the walls or floor?
In your location, you'll need an effective insulation envelope. You need to isolate the warm and cold air. If you don't, water will condense behind the wall and cause issues.
Two sclools ot thought are foamboard directly on the walld and a stud wall in front or a stud wall waay from the wall with a good batt insulation. It seems fiberglass batts has lost ground to other material.
If GBR sees this, I'm sure he will include some links to worthwhile reading material. In the meantime, check out the "Building Science" website.
 
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#3 ·
thanks for the response

Yes there is some efflorence, although since the interior drainage system was installed quite recently it is hart to tell if it still will continue to appear.
According to the installer's manual the drainage guarantees dry floor but not against wet spots on the wall

I would like to keep the total additional thickness limited, so I was planning installing the framing against the wall (with moisture resistant membrane directly against the wall) and insulation would be between the studs.

If I were to install plastic membrane directly against the wall to seal the moisture and direct possible water towards the tracking would it potentially cause some other kind of problem?

Attached a picture showing the situation
 

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#4 ·
When I did my basement in 1993, I metal studded the job, keeping the studs 1 1/2" away from the poured concrete. I love metal studs for the basement. Light, straight and will not mold. Of course back then, these were about $2.25-$2.75 a piece, comprable to the price of kiln dried 2x4's. I used fiberglass and wrapped the wall, front and back with 6 mil plastic. I sealed all outlet boxes.
I built a raised shelf system along the 21' foot wall with access panels(A/C vents). Once every year or so I used to check them out. Now it's 3-4 years. Fiberglass is dry, pink and clean.
You will not find this application in Build Science, but I wanted the back side of the fiberglass to remain dry.
Putting the wood against the wall could cause mold
 
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