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  1. #1
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    Default Maximum allowable bend in modified bituminous membranes

    Does anyone have a link to a standard for the minimum allowable bend radius for mod-bit at an outside corner (for example, over the top of a parapet wall)?

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    Michael Thomas
    Paragon Property Services Inc., Chicago IL
    http://paragoninspects.com

  2. #2
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    Default Re: Maximum allowable bend in modified bituminous membranes

    I'll see what I can find, but at inside corners they limit the bend to two-45 degree bends by installing cant strips along the bottom of the parapet wall.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  3. #3
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    Default Re: Maximum allowable bend in modified bituminous membranes

    I can make a few calls Monday morning, just though someone might have the info on hand.

    Michael Thomas
    Paragon Property Services Inc., Chicago IL
    http://paragoninspects.com

  4. #4
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    Default Re: Maximum allowable bend in modified bituminous membranes

    Based on skimming through this ( http://www.gaf.com/Roofing/Commercia...12-2525-v3.pdf ) and some other ones I found - I'm not sure that extending the modified over that type of outside corner is even allowed (for the reasons your photo shows).

    The outside corners described in the installation instructions is referring to, as an example, going around the end of a parapet wall, not going over top of the parapet wall. At least that is the way I read it.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  5. #5
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    Default Re: Maximum allowable bend in modified bituminous membranes

    Thanks for looking.

    Michael Thomas
    Paragon Property Services Inc., Chicago IL
    http://paragoninspects.com

  6. #6
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    Default Re: Maximum allowable bend in modified bituminous membranes

    Quote Originally Posted by Michael Thomas View Post
    Does anyone have a link to a standard for the minimum allowable bend radius for mod-bit at an outside corner (for example, over the top of a parapet wall)?
    I have always seen metal flashing at the edges. Have not seen the roofing material bent over the side as in your photo. Maybe a manufactor/supplier site might include some installation detai.

    Did find this cut that may help. Private Label Accounts - Metal-Era


  7. #7
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    Default Re: Maximum allowable bend in modified bituminous membranes

    Talked to GAF and Johns Manville, there is no minimum radius specified for outside corners because such bends (if present) must always be protected by an appropriate flashing.

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    Last edited by Michael Thomas; 08-20-2012 at 07:49 AM.
    Michael Thomas
    Paragon Property Services Inc., Chicago IL
    http://paragoninspects.com

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