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How should I insulate an octagon gazebo roof?

user-498659 | Posted in General Questions on

I am designing a 15′ Octagon Gazebo that will be a three season building with a door and windows. I am designing it with a 6′ cupola to accommodate a 52″ ceiling fan. The roof designed (2 by 8 rafters) is open with no ceiling joist.

This will be an “unheated” room, but I could see us using a space heater in the spring and fall to enjoy the gazebo a little longer (live in Minnesota). I was thinking it would be nice to have some roof insulation to keep the room from heating up too much in the summer. Can I insulate? If so what is the best option?

Thank you for any advice!

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  1. charlie_sullivan | | #1

    I would suggest polyiso foam board on top of the decking. Reclaimed foam is often available for much lower cost, if that's an issue.

  2. GBA Editor
    Martin Holladay | | #2

    First, you should check with your local code authority to see if there are any insulation requirements that apply. I doubt that there are, but it's worth checking.

    I agree with Charlie that you should consider installing rigid foam (either EPS or polyiso) on the exterior side of your roof sheathing and wall sheathing. Here are links to two articles that you might want to read:

    How to Install Rigid Foam On Top of Roof Sheathing

    How to Install Rigid Foam Sheathing

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