seal top of dimpled membrane at french drain
Randyj302
| Posted in General Discussion on
My sense tells me that caulking the top of the dimpled membrane in a french drainage system negates the system. Isn’t the dimpled membrane collecting water that may run down the walls? I imagine sealing the membrane 6-8″ above the slab won’t collect the water it was installed to collect. Radon is the pivoting discussion point. What are your thoughts?
Replies
I’ve been wondering about this very topic myself. I am planning on placing rigid foam directly to the wall, covering up the membrane.
Originally planned on adding membrane up the entire wall but price and difficulty getting the protect I chose just rigid foam route only.
However, the areas where I can’t install foam(appliances/oil tank) the small membrane gap will be open. Am I opening myself to higher Radon levels?
I recently had an interior French drain installed with a similar material that terminated at the floor. I decided to caulk it shut because I had a radon system installed and the installer told me it was the only way to ensure a good result.
I ran it by the company who did the French drain and they said for me it would be a non issue because when the trench was dug for the new tile each hollow portion of block had a 3/4 inch hole drilled in the bottom of it where water could run down and out to the tile. The company said with the drainage holes under the slab by the footer no water will ever come through the wall.
If you wanted to you could always buy more dimple mat and extend it to the top of the wall and seal it off there. With it done properly you could be sealed tight enough for radon mitigation and still be able to catch any water that would come through. I personally would have extended the dimple mat for mine but I also have vertical beams ever 18-24 inches due to static pressure bowing the walls.