Why is there condensation in between polyiso board and Roxul insulation in basement walls?


Why is there condensation in between 1.5" polyiso board and roxul insulation?

Tyler Norrie Feb. 9, 2021Last updated: Feb. 12, 2021

Hi guys im from Canada and I recently finish studying and insulating my basement. I used one and a half inch polyiso board insulation glued to the wall with adhesive and I left a half inch Gap all around the board to spray foam. In front of the wall I frame to buy for walls and insulated with Roxul insulation Batts I went to go do some electrical work today and pulled back a bath and noticed that there was a bunch of condensation and a little bit of mold in between the bat and the polyiso. Did I do something wrong here? The humidity in my basement is 45%.

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