Basement wall assembly
We are building a house with a daylight basement (three sides below grade), and though the soil is good, rainwater doesn’t drain very well. We have a perimeter drain in, connected to an interior drainage pipe around the garage (which is a few feet lower than the basement level). We unfortunately did not implement a capillary break between the footing and the foundation wall, though we do have a drainage mat and waterproofing on the exterior of the wall.
We currently have fiberglass batts (R21) specified for the walls. I’d like to add 1″ of XPS between the wall and the fiberglass batts to minimize condensation/adsorption, though the walls need to dry in and we are sitting in the middle of rain and cold weather (20-40 deg F). With the fiberglass batts, we would use dehumidifiers and fans to dry in before installing them, though apparently the foam would need to go on the wall right away so that framing could be then built over it.
Should I be concerned about the 1″ of XPS (~1.0 perm rating) not allowing the concrete to dry to the interior before the fiberglass batts and wall coverings (3/4″ drywall) are installed? The builder is specifying that the XPS be attached to the concrete walls with expanding foam (no tape).
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