Irregular Basement, Interior Perimeter Drain, and Radon Mitigation
I am planning to finish the basement in my home and I would like some input about how to tackle adding insulation, the existing interior perimeter drain, and radon. The home was built in 1930, no exterior insulation or vapor barrier, climate zone 4A (Westchester county, NY). I have radon readings of about 4.0 pci/L. There are rock outcroppings in the basement – about 20 linear feet where the interior drain and dimple mat follows the rock outcroppings (not the basement walls). See attached picture.
Does it make sense at all to try to seal the dimple mat where I can to prevent radon from coming into the basement, even though I can’t seal the dimple mat at the rock outcroppings? And if so, how to seal the dimple mat to the EPS? Or instead of sealing the dimple mat to deal with the radon, perhaps it’s better to actively or passively venting the perimeter drain with a pipe to the roof? I’m looking for the simplest/most economical and effective solution.
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