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    Minimum roof pitch

    Minimum roof pitch

    New postby mmarcley on Sun Dec 06, 2009 8:41 am

    In building a dormer, I need max height at the low end and therefore need absolute minmum roof pitch. How low can I go?
    Posts: 3
    Joined: Sat Dec 05, 2009 2:06 pm

    Re: Minimum roof pitch

    New postby Jerry Peck - Codeman on Sun Dec 06, 2009 11:19 pm

    Hi Mark,

    Depends on the roof covering type.

    If shingles, most manufacturers say down to 2-1/2:12 slope with some saying down to 1-1/2:12 slope with special underlayment conditions.

    If metal roofing such as standing seam, 5-V crimp or similar styles, most manufacturers say down to 4:12 slope.

    If concrete tile or slate, most manufacturers say down to 4:12 slope.

    If modified bitumen single ply and other similar roofs, most manufacturers say down to 1/4:12 slope.

    Also note that the end of the dormer at the window might not need to meet a 7 foot ceiling headroom.
    Jerry Peck - CodeMan

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    Construction Litigation Consultants, LLC.
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