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

Mooney wall vs. rigid foam for a kneewall attic

Nolan126 | Posted in Energy Efficiency and Durability on

Cape Cod style house in kansas city (all weather patterns) . Freezing upstairs that will probably cook in the summer. I have been scouring these forums and others how to fix this issue. I had been settled on a mooney wall on the 2×4 knee as i have the room. I planned on leaving the current insulation in place, if possible, to reduce material waste and cost. I found a dense packing machine (menards krendl 425 dual outlet), found where to buy the correct fiberglass (one of my local wholesale distributors) and had calculated how much material I needed. I have already started using rigid foam cut outs to air seal the floor joists with can foam to seal more. But someone recently just asked why I didn’t use rigid foam over the exsiting batt insulation instead of the mooney wall.

Is this the way to go? Again I have the room to get in and out. And can I leave the current batt in place and just put the rigid in top? Or should I remove the paper backing first?

Any information would be greatly appreciated. This project is making my head spin.

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.


  1. GBA Editor
    Martin Holladay | | #1

    Can you tell us your name? (I'm Martin.)

    Rigid foam can certainly be used on a kneewall. For more information, see this article: “Two Ways to Insulate Attic Kneewalls.”

    1. Nolan126 | | #2

      Updated my name. I am assuming that this method would be better than the Mooney wall?

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |