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Roof insulation

Plippe | Posted in Energy Efficiency and Durability on

We are replacing the roof of our home in climate zone 4A with a full tear off and have decided to go solar.  Since the building is an old church with 25 foot ceilings and no attic or insulation as far as we can tell, we think this is also the best opportunity to add insulation between the plywood of the roof and the wood ceiling of the church. The question is what insulation would be best?  Thank you in advance for any advice.

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  1. GBA Editor
    Brian Pontolilo | | #1

    Hi Pamela,

    I think you are describing a cathedral ceiling (aptly named for your building). Since you are considering insulating the roofline, I assume that by full tear off, you are talking not only about the roofing, but also the sheathing, which would give you access to the rafter cavities. First, I recommend that you read this article about insulating cathedral ceilings: http://www.greenbuildingadvisor.com/article/how-to-build-an-insulated-cathedral-ceiling

    You may also consider installing some or all of the roof insulation above the new roof deck. This article will help you determine if that is a good idea for your project: http://www.greenbuildingadvisor.com/article/how-to-install-rigid-foam-on-top-of-roof-sheathing

    Finally, keep in mind that air sealing will be super important for your insulation to be effective and for your roof assembly to be healthy. Wood ceilings are notoriously leaky, so part of your plan should be to remedy that.

    1. Plippe | | #2

      Thank you. I will share with my contractor.

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