GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X 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

Paper-faced fiberglass batts in attic, mixed with cellulose?

CTSNicholas | Posted in Green Products and Materials on

On new construction – I am thinking about doing 12″ Paper Faced Fiberglass for parts of the roof that are going to be hard to get to (hip roof) and then using cellulose everywhere else after the ceiling is drywalled. I know that adding cellulose on top of existing paper-faced fiberglass is common.

My question is, is there anything wrong with mixing the two types? I can easily blow in cellulose for 75% of the attic area, but the far corners will be very difficult, and insulating from below before hanging the ceiling drywall would be easier.

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. Expert Member
    Dana Dorsett | | #1

    It's perfectly fine to install cellulose over asphalted kraft faced fiberglass, no matter how deep or which side of the fiberglass the facer is on.

    At high depths of cellulose it may compress the batt a bit, but that only increases the R/inch of the fiberglass. It's the total depth (of compressed batt + cellulose) that matters.

  2. GBA Editor
    Martin Holladay | | #2

    I think your question is different from the one that Dana answered.

    Yes, you can insulate part of your attic floor with fiberglass batts, and the rest of your attic floor with cellulose. In all areas, pay attention to airtightness.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |