Hello Adam, sorry, I didn’t mean to hijack or derail the thread. I have now read up on the European equivalent to perms, which I believe is Sd-value. I will make a separate post on this topic.   I am also building an ICF house, when I researched tapes I found the Siga Wigluv tape specifically mentions EPS as a substrate.    https://www.sigatapes.co.uk/Wigluv_100/p4850575_17610284.aspx