XPS vs. EPS Below Grade
So I know there lots of information regarding XPS vs EPS for below grade applications. The consistency of this information is questionable, and now I am trying to figure out what to do for my situation.
My concern right now is insulating the sides of the trench for the footing/stem wall which sits 30″ below grade
Based on a recommendation from a friend, I set out and collected as much used XPS foam as I could find. I have almost all foamular 250 and 150. Some of it is 150 with a thin plastic membrane for moisture control (old stuff?). Additionally, some of this has been stored in less than optimal conditions and has its share of mouse damage (both chewed on, and a few sheets had some mouse pee smell). None of this bothered me as it was all slated to be buried.
Fast forward to now, and after some research, found some compelling research on how after 15 years underground, the EPS retained far more of its R value and retained less moisture (here is an artical I saw a few times since then: https://plastifab.wordpress.com/2019/08/13/the-great-debate-eps-vs-xps-for-below-grade-applications/).
So now I have to wonder, should I be using EPS instead of XPS and save the XPS for the walls of the building? (the roof will be getting a 2″ layer and the walls 1″). The crummy part about this, is I want to avoid using XPS that has any kind of bad smells from storage/mice/etc in a place that might make the building smell.
So the question is: What would you do? Are there places below grade, say, the INSIDE of the trench footing, that would be ok for the XPS then use EPS on the outside? Can smells be effectively washed off of the XPS?
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