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mitre angle??

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  1. #1
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    Default mitre angle??

    Been searching on line for a roofing chart without sucess.
    Knowing the depth of knowledge here, I'm certain I'll get a result!
    I have a rafter @ 5500mm long with a fall of 200mm over entire length.
    Q: What angle does mitre need to be cut too & what is formula for it's calculation?
    Kind regards,
    Sandman.

  2. #2
    ian
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    Default

    I have a rafter @ 5500mm long with a fall of 200mm over entire length
    before you cut that rafter, what are you covering the roof with?
    if it's wriggly tin (corrugated iron) a 1 in 28 fall is lot less than the recommended minimum of 1 in 12


    ian

  3. #3
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    Thanks Ian.
    I am researching for a mate. I will ask what he is going to cover it with.
    Regards,
    Sandman

  4. #4
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    Default

    angle =acos(adjacent/hypotenuse)
    = acos(200/5500)
    = 87.9 degrees

    On MS scientific calculator (press each button as below)
    Make sure degrees is selected.

    200 / 5500 =

    tick box "inv" then press the cos button

    if ms calc does not have all the bttons select "view" then "scientific"
    Last edited by ivanavitch; 7th Dec 2007 at 11:30 PM. Reason: not everyone has scientific selected

  5. #5
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    Default

    A bit confused here, are you talking about a common rafter side cut?
    Or your use of mitre makes me think you might want the jack rafter top cut. If that's the case it's so close to 45deg it doesn't matter.

    If it is your side cut, as already posted by Ivan, it is say 88 deg which is a two degree pitch, and custom orb requires 5 deg minimum as Ian has already pointed out.

    Klip-Lok 406 0.42 will do a 2deg pitch and the thicker stuff will go down to one degree.

    Cheers
    Bill

  6. #6
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