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

Rockwool for walls and roof

BlueSolar | Posted in Green Products and Materials on

Hi all – Mineral wool insulation seems ideal for both walls and roofs.

But someone at GBA said it was better suited for walls than roofs (I can’t find the source). Why might mineral wool be less suitable for roofs? I’m thinking of batts in particular – obviously the boards wouldn’t work.

Thanks.

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. Jamie B | | #1

    It's great for roofs in my opinion.

    Jamie

  2. Expert Member
    Rick Evans | | #2

    BlueSolar,

    Mineral Wool batts can work great between rafters so long as a few rules are followed:

    1.) batts are air-permeable (fluffy insulation) so all six sides of the batt must be covered to avoid convective loops. You'll need some kind membrane or wall board in the attic.

    2.) You'll also want an airspace under the sheathing so baffles are needed so fully enclose the mineral wool batts

    3.) Or you can skip the air gap and add a layer of rigid foam or mineral wool on the exterior of the sheathing to 'warm it up' using proper climate-specific ratios.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |