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Rake overhang framing on top-side insulation retrofit

gabrielsolomon | Posted in Green Building Techniques on

Can  you build a rake overhang by standing lookouts on top of the existing roof deck? (see drawing.) I will be putting 6″ rigid insulation on top of my roof.

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Replies

  1. walta100 | | #1

    I think it depends on your local snow load. Your picture would likely be fine in southern Arizona.

    My guess is that with 24 inches of snow and 24 inches of overhang. The eave overhang would certainly collapse and the rakes should be OK as long as the cantilever is less than 1/3. The eaves are supported by 2X4 on the flat my gut says 8 inch max.

    There are people called engineers that make a living designing this stuff. The safe bet is to pay one.

    Walta

  2. gabrielsolomon | | #2

    Thanks Walter. I'm guessing my engineer may ask that the rake lookouts go back 16 inches to the next rafter. The eaves will have additional framing that is not shown.

    I ask only because I've never seen lookouts standing on top of rafters before.

  3. Expert Member
    Michael Maines | | #3

    Gabriel, you can, but how far you can extend depends greatly on your location and particular situation. Like Walter said, it would be smart to hire an engineer if you plan to extend more than a few inches.

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