GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Using Polyiso in Basement Remodel

| Posted in General Questions on

Hi,
I live in Maryland zone 4a Marine.

I am finishing my basement and using 1″ polyiso foam board as the thermal barrier for 2 reasons – it’s more fire retardant than the other foam boards and it has a higher R value/inch. (1″ polyiso=R6 v 1″ XPS=R5).  I read that polyiso loses R value in cold weather but that there isn’t a concern when used in interior applications.

I read that polyiso shouldn’t be used because it can wick up moisture.  However, I read that only happens if the polyiso is made with fiberglass.  I understand that RMax R Matte Plus 3 and John Manfield AP Foil Faced are two products that do not use fiberglass and therefore won’t absorb water.  I was going to raise the boards a half inch off the ground to be safe.

I also understand that since it is being used inside the basement, that it doesn’t matter which side is facing the interior v the concrete wall.

I would appreciate your thoughts/comments.
Thanks!
Sue

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |