Ventilation question for new coop

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by Buster, Feb 16, 2009.

  1. Buster

    Buster Back to Work

    Ok, I'm building a new coop this week and I need some feedback on gravity ventilation. If I understand it correctly, the warm air rises, then as more warm air rises, it pushes it down the roof line and out the vent. Maybe I'm way off-base on that, but that's how I understand it.

    So, if my theory on it is correct, then can I leave space between the rafters between the top of the wall and bottom of the roof open (with hardware cloth over it) on a shed-style roof and have the warm air circulate out? I am planning on the roof being clear plastic to bring in more light and want to make sure I don't create a greenhouse effect that I can't ventilate.
     
    Last edited: Feb 16, 2009
  2. DawnSuiter

    DawnSuiter Chillin' With My Peeps

    Hot air rises... so it would push UP and out the roofline.

    I have about 8 inches of vent on either end of the shed roof, using clear & smoked panels alternating on the hen house. In the summer you see them staying in the shadow of the smoke panels because the clear are like having no roof.
     
  3. bills

    bills Chillin' With My Peeps

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    You have the correct idea about the air circulation. If you mean a slant roof, rather than a peaked roof, the vents between the ends of the roof joists work well. A screened window that opens is also a benefit, as you can add more fresh air on the hotter days, as well as light.

    The plastic roof idea I question.

    One- It will become a hot greenhouse inside, during any sunny days., ventilation to prevent that would have to be extreme, IE electric fans.

    Two- Condensation will more likely happen, as the plastic has no insulating value.

    Three- It will offer no warmth in the winter, again no insulating value.

    Four- It may not be as strong (depending on your construction methods) to withstand heavy snow loads.

    Five- extremely noisy inside when it rains, or hails. I'm not sure but this may affect the chickens health, IE. lack of sleep, if it rains for several days.

    I'm sure there are other negative points as well, but I wouldn't use it as the material of choice for the coop roof. It works good as a wet weather roof over a smaller outside run.
     
  4. patandchickens

    patandchickens Flock Mistress

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    Ontario, Canada
    I agree with every single word that bills has written here [​IMG] (Well except the noise thing, maybe, but I dunno, he *could* be right [​IMG])

    Seriously. Your ventilation plan is good; your clear roof plan, almost certainly *bad*, unless this is in a nearly continually shaded area even in winter. It takes a whole LOT of air exchange to offset the heat gain from a clear roof, and especially in summer when the air coming in isn't all that cool to begin with...

    Good luck, have fun,

    Pat
     
  5. DawnSuiter

    DawnSuiter Chillin' With My Peeps

    I should've also said I guess that my hen house also only has about 50% solid walls... or rather 50% of the wall areas are completely open... and we don't have snow loads for sure.
     
  6. Buster

    Buster Back to Work

    Thanks so much for all the input. I want to clarify where the coop is going and see what your opinions are. I have a line of 50' spruce trees to the north of my house. I am going to put this coop on the backside of the first three trees in the picture. The branches of the trees almost completely cover the coop. It will be a shady spot except for the evening sun and I do plan on having windows in it. If I went with metal roofing instead, won't condensation build up on it?
     
    Last edited: Feb 16, 2009
  7. Buster

    Buster Back to Work

    Here is the pic of where I'm putting the coop:

    [​IMG]
     
  8. patandchickens

    patandchickens Flock Mistress

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    Hm. Well, are you absolutely totally 100% positive the roof area will not get direct sun during the main part of the day, not even on June 21 when the sun is much further overhead? (which will depend how far under the trees the coop is). Unless you are 100% sure from experience, I'd actually do the math on where the sun will be and then go out there with a transit or at least a protractor and DOCUMENT whether it'll be ok.

    But *if* it is genuinely truly not going to get anything but evening sun, then it would be ok.

    You will get nearly the same amount of condensate as you would on metal, however, sorry [​IMG] Meaning you may need winter insulation...

    Good luck, have fun, nice healthy-looking trees! [​IMG],

    Pat
     
    Last edited: Feb 16, 2009
  9. Buster

    Buster Back to Work

    Ugh. Do you want those trees? I don't like them and if I could sell them all I would.

    I guess I can do OSB on the roof with metal over it. That's how my current coop is and I don't have problems with condensation.
     
  10. Steve

    Steve Ye Olde Henhouse Builder

    Check your cost of metal vs. shingle.

    Since you are already talking osb, I would shingle with a good 30 yr. shingle.

    Adding metal to the already established osb would cost more than shingles over the osb....least it does around here.
     

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