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How do you remove moisture and condensation from basement walls?

Aaron Keating Published: July 27, 2019, 4:51 p.m.Last updated: Dec. 1, 2019, 5:21 a.m.

We recently moved into a 15 year old home and have a smell coming from the basement. We had a mold inspector test and look everywhere and found no issues. We took down our insulated wall panels and there is a clear plastic barrier then pink fiberglass insulation right on the foundation. The insulation and barrier/plastic sheet are from floor to ceiling. We opened it up and found the insulation is very damp on the foundation side. There is no mold in there but my hand got wet in the spots I stuck it in. We have been running a dehumidifier for a couple of weeks and it hasn't fixed the issue or smell. I smelled behind the insulation and found that to be where the smell is originating...just damp concrete and insulation. There is no wood as the wall frames are metal. No leaks from the outside coming in either. 

I feel like the insulation is wrong and the insulation and the plastic barrier are creating the issue. What should be done to remedy this? Replace insulation with foam insulation and have no plastic barrier? Would it be wise to pull down all the insulation in the meantime to dry things out or would that cause other issues? We live in the GTA.

Thank you,

Aaron

Responses (3)

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Aaron Keating July 30, 2019, 9:20 a.m. Reply

Hi, if we replace the insulation with spray foam or rigid foam and do not change the exterior waterproofing, will that stop the moisture from coming inside? Or is digging down and adding a waterproofing membrane and also replacing the insulation the only way to fix this? I have read that the external digging and waterproofing is very expensive. 

Thank you,

Aaron

Ecohome
Ecohome July 30, 2019, 10:48 a.m. Reply

 

Yes, doing it from the outside would be ideal, that way you can install a drainage matt and weeping tile, and by insulating the exterior you keep the concrete warm which protects it from cracking due to the annual freeze / thaw cycle. You would also get a few more inches of room on each side of the wall on the interior. If you've got the budget for it and the ability to get around the house with a small excavator I'd say go for it, but for sure it's going to cost more. It's definitely the 'best' way to do it but it can be  a huge hassle with porches, decks and laneways, and then having to cover the foam with cement board or parging, so we don't try too hard to push people in that direction even though it makes for a better build.