new help with roof addition

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by Vickir73, Oct 21, 2010.

  1. Vickir73

    Vickir73 Chickens Ate My Brain

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    Sep 9, 2010
    Leggett/Livingston
    First of all, please forgive my terminology. I'm new to the whole construction thing, so I'm describing everything the best I can [​IMG] Here's the existing coop. I've posted more recent pics with the windows added, but this is the best pic of the roof. I'm adding a 16 ft addition on the west side (the side opposite the highest point of the roof). The EASIEST thing to do would be to just lip the new roof under the low end of the old roof; however, I would like my ceilings in the new addition to be no lower than 6 ft. Is this possible? What if I slanted the ceiling of addition so the lowest point would be 5 ft?? I really don't want to do this because everyone in my family is over 5 ft and I know we would constantly be banging our heads on the door.

    Should I just take the existing roof off and make a completely new roof???? Any ideas??? Does anyone know any sites that might give me ideas???

    [​IMG]
     
  2. patandchickens

    patandchickens Flock Mistress

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    Apr 20, 2007
    Ontario, Canada
    The key piece of info you've left out is, how high is that wall you want to attach the addition to [​IMG]

    Basically though it is really easy to calculate, just find out how high you could possibly put the roof tin, subtract 2" for the thickness of roof tin and purlins and also subtract [thickness of rafters plus 1"], which will tell you maximal head clearance possible on that end of the addition. Then figure out what your minimum roof pitch needs to be and do the math. Minimum acceptable roof pitch depends on your local snow load and wind load and rainfall and what roofing material you will use, but is unlikely to be less than 1-2 ft in 12 even in snowless areas, and in snowy areas should probably be more like 3/12 at least. Lower pitches leak more, and require you to use tin rather than shingles (tho you'd probably be using tin instead of shingles *anyhow*).

    For instance, if you have 7' of usable headroom at the one end, and want the roof to stick out 16' away from that shared wall, and have a 1/12 pitch (which is not going to work in snowy areas without SERIOUS rafters, and will tend to leak under lotsa rain, but may be ok for dry and warm areas), then the roof will slope down 1'4" giving you only 5'8" of headroom at the low end. (Redo with whatever your actual numbers are [​IMG])

    Please be aware that if you are really meaning the addition to be 16' wide, i.e. it will extend 16' out to the side of the existing wall, you are going to need either some SERIOUS lumber, or some internal support posts, as 16' is an awfully long span to go unsupported and if it *does* it will require some significant sized posts including beefing up the existing wall that will hold half of it. Indeed from the looks of the existing building you probably ought to add some posts to support that end of the addition ANYhow, since the it appears to be "not overbuilt".

    Good luck, have fun,

    Pat
     
  3. Vickir73

    Vickir73 Chickens Ate My Brain

    279
    2
    111
    Sep 9, 2010
    Leggett/Livingston
    thank you. The height of the roof is 8 ft tall. I've been working on plans a week (or so). There will definitely be plenty of support for the new roof addition I just wasn't sure how the easiest/best way to do it was. I will definitely be posting pics when I'm finished. I'm in East Texas, so the snow is not an issue [​IMG] I'm going to try to hip the new roof onto the old one, so we'll see. . .
     

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