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XPS in basement – Insulating over drainage board

| Posted in General Questions on

Hi all,
I’m planning to have an interior French drain installed prior to finishing my basement.  After the drain is in, I intend to apply XPS against the wall and frame out the wall directly against the XPS.  I have a couple of questions about doing this:

1) The contractor installing the drain states he will install drainage board from the drain to about half way up the wall (could just be dimple mat but says it will be about 1 inch thick so not exactly sure of the exact product).  I’m not sure how to install the XPS in this case – should I adhere it directly to the drainage board?  How should I transition from the XPS to the drainage board half way up the wall.

2) I have a “step” halfway up my wall where I guess they changed the wall block size.  My plan is to cut XPS to the shape of the step to leave no air gap between the wall and the insulation.  When I frame it out, I plan to just go straight up, which would leave a couple inch gap between XPS and framing on the upper half of the wall.  I can’t see why there’d be any issue with this, but thought I’d check with you all for your thoughts.  I’m attaching a picture of the wall, with the “step” for reference.

Thanks in advance – I really appreciate all the advice I’ve gotten from this forum and site.

GBA Prime

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