Zone 4 interior basement insulation in relation to dimple board
I have an interior waterproofing solution installed and now I’d like to finish my wall. What isn’t clear to me is how to account for the couple of inches of dimple board/miradrain material that is showing at the bottom of the wall. Do I merely cut the XPS foam to end above this dimple board? If so, should I be worried about any fiber insulation in the framing touching the surface of the dimple board and should I still seal the bottom of the XPS board? Or do I extend the foam just long enough to tuck into the top of my dimple board? If so, do I use tape at that seam or just leave it open? I can’t find any information about this online.
To complicate matters, the dimple board extends along the entire length of the wall, only part of which will be finished. So this means that there will be airflow along the length of the dimple board, so I’m having trouble thinking through the ramifications in terms of air flow and temperature from the unfinished section into the finished section.
What, if any, insulation should I put over the unfinished section?
Thank you.
S H
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
A picture would be useful here.
It's unlikely you'd be able to get a reliable seal with tape, but you might with can-foam.
If there's ANY chance of water seepage at all it's best to stop any fiber insulation above the dimple-board/foam seam. If you're insulating the flooring, run the floor foam right up to (or under) the wall foam.
EPS is a lot greener than XPS due to it's very low impact blowing agent (pentane). In 50 years when the HFCs all leak out of the XPS it's performance will be the same as EPS of the same density.
S. H.,
We need a better description of "couple of inches of dimple board/Miradrain material that is showing at the bottom of the wall."
Is this material installed just between the slab and the wall/footing? Or is there are continuous vertical layer of this material from the footing to the top of the wall?