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What is a cathedral ceiling?

Insular | Posted in Energy Efficiency and Durability on

In reading about insulation I see recommendations about cathedral ceiling vs other types.

What exactly is a cathedral ceiling, and specifically is the ceiling in a an attic considered a catheral ceiling?

In this particular attic, the ceiling is somewhat high in the middle of the attic (maybe 9 feet), but slopes down to height of zero at the edges. It’s your basic upside upside down V.

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  1. user-1140531 | | #1


    If you removed the floor in your attic, it would a cathedral ceiling, which is also called a "vaulted ceiling." If you are standing on the floor of a full story, and looking up, and if it is open right up to the bottom side of the roof, that bottom side is a cathedral ceiling. The insulation has to be in that ceiling system that is part of the roof.

    In an attic, the insulation is typically on the floor, which is the ceiling of the room below. Then the roof of the attic is uninsulated.

  2. GBA Editor
    Martin Holladay | | #2

    A cathedral ceiling is an insulated sloped ceiling.

    More information here: How to Build an Insulated Cathedral Ceiling.

    By the way, since you are asking a lot of questions lately, you might consider using Google or the search bar on the GBA site to find some of the answers to your questions -- with the simple method called "search."

  3. Insular | | #3

    Martin and Ron, thank you for you patience. Hopefully as I learn more and talk to my builder/contractor, my questions will become more pointed (and less frequent!)

    So if I keep the insulation in the floor of the attic as Ron said is typical, I will not have to worry about warm air in the attic warming the roof and creating an ice dam on the roof correct? (I will be adding gutters to a house that never had them, so ice dams would be a concern.)

    But moisture rising up from house and condensing on the roof could be an issue, if I am not mistaken.

    What is the best material for the floor of an uninsulated attic in zine 6A or 5A. Is it important to use an air barrier?

  4. GBA Editor
    Martin Holladay | | #4

    Believe it or not, the search function on the GBA website actually works.

    Information on preventing ice dams: Prevent Ice Dams With Air Sealing and Insulation

    Information on air barriers: Questions and Answers About Air Barriers

    Information on everything: How To Do Everything

  5. Insular | | #5


    Much appreciated. I read through Prevent Ice Dams With Air Sealing and Insulation and a few dozen of the comments.

    It seems that there is not a consensus as to whether it is best to insulate the attic floor or the roof (or both). Would you say that is true?

  6. GBA Editor
    Martin Holladay | | #6

    If you aren't living in your attic, the insulation goes on the attic floor.

    If you are converting your attic to living space, or if you want to create an unvented conditioned attic to bring your attic ductwork inside your home's conditioned space, then the insulation follows the roof slope.

  7. Insular | | #7


    I can't tell you how thankful I am for your help. Now I feel I can talk with the contractor.

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