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

Finished cathedral ceiling insulation options

Mhw103 | Posted in Energy Efficiency and Durability on

Our den is extremely cold and have discovered that the roof has no insulation. Very thin bat insulation exists on the ceiling itself. This we found out when handyman took a look through one of the high hats.

Considering blown cellulose insulation so we don’t destroy the Sheetrock, but I am concerned that its particles will come out thru the high hats and ceiling fan and will breath them. No estimate.

Got an estimate -$2,600 to take down one side of the Sheetrock panels and open a hole on the other side to place bat insulation on roof and replace existing insulation with a thicker one. (One side has space to work with, the other side doesn’t).

Considering health vs practically tearing the ceiling, which one do the experts recommend?

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

    Your "high hats" (recessed lighting fixtures) are a big problem. If they are leaky enough to allow insulation particles to filter through your ceiling -- and they probably are -- then the fixtures should be removed and replaced with surface-mounted fixtures.

    There is no way to fix the problem of recessed can lights in a cathedral ceiling short of removing the fixtures and placing them in a dumpster. Recessed can lights should never, never be installed in a cathedral ceiling. For more information on this issue, see Recessed can lights.

    Once you've solved the recessed can problem, you can install insulation on your ceiling. This article will explain your options: How to Build an Insulated Cathedral Ceiling.

  2. Mhw103 | | #2

    Given that the roof is not insulated, Would you recommend cellulose blown insulation or bat insulation ?

  3. davidmeiland | | #3

    It sounds like this is partly inaccessible attic, partly cathedral ceiling.

  4. GBA Editor
    Martin Holladay | | #4

    If you are talking about a cathedral ceiling, there are several possible ways to insulate the assembly. Some approaches are vented, while other approaches are unvented.

    To learn about all your options, read this article: How to Build an Insulated Cathedral Ceiling.

    If you are talking about the floor of an accessible attic, I would recommend a deep layer of cellulose.

  5. fitchplate | | #5

    Dense packed cellulose will actually airseal itself around and against fairly wide openings, cracks, seams, etc, but the law requires clearances so the cellulose is out of range of the heat of recessed lighting. Your problem is not the fugitive particulate, it would be the combusiton of cellulose that is againt and possibly inside the hot boxes.

    Here is an online Technical Bulletin from one of the country's largest cellulose manufacturers:

    There are foam and metal boxes, as well as compliant light cans, but this just isn't done anymore:

    Nothing but horror stories abound in the articles and research referenced on this website with the use of FG batts in cathedral ceiling assemblies.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |