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

Insulation

jam1030| Posted inGeneral Questionson

有2×10楼板搁栅。位于2区,would it be a bad idea to use R15 rockwool which is 3.5” thick pushed up to bottom of joists and then apply osb or polyiso to bottom of joist to seal and protect insulation?
Or just use 2” of closed cell spray foam?

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

  1. GBA Editor
    Brian Pontolilo||#1

    Hi Jam1030.

    Air sealing this floor assembly is just as important as R-value. If you a couple inches of polyiso, detailed as an air barrier on the bottom of the joists, your R-value will likely meet the code in your area. Then, any insulation you put in the joist bays is a bonus. Again, pay close attention to air sealing.

  2. walta100||#2

    The answer to your question depends in what is under your joists. If you have a basement or a sealed crawl space I think it is a bad idea.

    If you are on piers I would not want to have polyiso exposed to the element.

    Walta

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |