Insulating Basement with Poly Over Sill Plate
I’m in the process of finishing my basement, and trying to figure out if I should remove poly sheeting before adding insulation. I currently have 6mill poly sheeting running from sill plate down to a drain tile in the floor around the entire basement, similar to the attached photo except no stud wall built yet. Purpose of the poly is to channel water down wall and into drain tile. I’m planning to insulate according to the https://www.buildingscience.com/documents/information-sheets/basement-insulation article, but it makes clear that “No interior vapor barrier” should be used to allow for drying to the inside.
I’ve got 2″ xps that’s ready to install over the poly, but thinking I should remove the poly sheeting first. Will I have issues if I leave the poly up? Seems like the interior surface of the XPS should be warm enough to avoid condensation. I’m in NY climate zone 5.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part