Ridge/Soffit Ventilation in a Cold Climate

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by CityChook, Aug 3, 2008.

  1. CityChook

    CityChook Chillin' With My Peeps

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    My Coop
    I have searched this topic to death and am still so confused...

    We live in Minnesota. Long, cold, bitter winters. We have 4 Buff Orps. Our new coop is 6x8 with insulation on all 4 walls and the roof, two windows (south and east sides), a 15 inch pop door, a ridge vent that runs the entire length (west to east, 8 ft) of the coop, and soffit intake vents. It DOES NOT have a dropped ceiling - the insulation backs up to the plywood of the roof. My DH also put in two (small - like 4 inch) round vents at the gable end of the east side.

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    I do not understand construction. I do not understand ridge vent ventilation. I am just looking at this with a woman's common sense questioning eye.

    My question: How is it possible for the air to move along the inside of the roofline from the soffits to the ridge when the insulation is in the way?

    AND, if the insulation meets at the peak, and covers the ridge vent, then how is it supposed to pull any air/moisture out of the coop? Seems to me that the moisture would get caught in the insulation - and that would be bad, right?

    Is the ridge vent primarily to keep my roof from rotting and not to ventilate my coop area?

    I am pushing for more ventilation. We have space in the gables but the roof trusses are in the way, so they might be a little odd. My DH says that the two small vents in the east gable, along with the open popdoor, along with the ridge/soffit ventilation will be sufficient. My goal: to not be out in the backyard, in 0 degrees and snow, with a saw cutting holes in my million dollar coop because it's too wet inside. All the time muttering "I told you so."

    He thinks I'm over-reacting, which admittedly, I can do at times. Alas, I know NOTHING about insulation/ventilation, so I am having trouble selling my opinions. And we're trying hard to wrap up this coop construction (big relief sigh) and tempers are a little short.

    Maybe I've read too much internet advice? Can you help calm my nerves and get off my husband's back?
     
  2. fullhouse

    fullhouse Chillin' With My Peeps

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    MI
    There is a piece of plastic that fits between the roof rafters and acts like a path for the air to go up and under the insulation should you need it in a knee wall (or similar wall). Ideally you would insulate the horizontal ceiling and leave the rafters open like an old attic. If you cover the vent, you have no vent. Lessons learned insulating a 100yo house. [​IMG]

    ETA the plastic pieces are called baffles [​IMG]
     
    Last edited: Aug 3, 2008
  3. patandchickens

    patandchickens Flock Mistress

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    Ontario, Canada
    Quote:For the soffits, he *should* have installed some sort of baffle, be it storebought or just made out of a piece of wood, to hold the insulation back away from the soffit vents and give air a clear path of travel. So that would be ok (although insufficient as a sole source of ventilation - see below)

    Since as near as I can tell, the insulation is continuous (or at least taped together) along the underside of the ridge, then yes, all your ridge vent is doing is letting a very small amount of windblown rain or snow in to dampen your insulation. Also without a vapor barrier up there you may get additional sogging of the ceiling insulation.

    Is the ridge vent primarily to keep my roof from rotting and not to ventilate my coop area?

    My guess is that it seemed like a good idea when he was ordering materials but forgot about it when it came time to install the insulation [​IMG]

    I am pushing for more ventilation. We have space in the gables but the roof trusses are in the way, so they might be a little odd. My DH says that the two small vents in the east gable, along with the open popdoor, along with the ridge/soffit ventilation will be sufficient. My goal: to not be out in the backyard, in 0 degrees and snow, with a saw cutting holes in my million dollar coop because it's too wet inside. All the time muttering "I told you so."

    To be honest, unless you have your window fully open I think you have RADICALLY insufficient ventilation, and it's not like you're going to be able to have the window open wide in midwinter [​IMG]

    Your husband needs to understand that while the ventilation he's built is great for a storage shed, chickens produce HUGE amounts of water vapor and (via their poo) ammonia fumes. The water vapor is a much bigger issue than you might think, because cold+damp=frostbite, and damp at *any* temperature = respiratory disease, many of which are not very curable once you've got 'em.

    In a relatively small air volume like this, I would suggest something like 0.5-1 square foot of ventilation per chicken as a ballpark starting point (can't give a more exact number b/c it depends on things like how humid your weather is, how often you clean the coop, how windy the coop's site is, etcetera).

    If your husband requires more convincing, look up online or in Gail Damerow's chicken raising book for numbers for old- and modern-style commercial poultry houses.

    If it were me I would cut rectangular ventilation ports between the studs on either side of the window, right up under the top plate of the wall so they'll be protected by the roof overhang; and matching ones on the opposite side of the shed, probably between every stud not just two. protect them with hardwarecloth, obviously. You can make little flap or slider-style covers to allow you to close them off as needed depending on the weather, e.g. in a blizzard shut the upwind ones [​IMG]

    Bigger gable-end vents would sort of be ok but will have the disadvantage of allowing windblown snow/rain in to further dampen your coop (thus requiring them to be closed off a lot of the time, which means you often can't *use* that ventilation).

    Good luck,

    Pat​
     
  4. Firefyter-Emt

    Firefyter-Emt Chillin' With My Peeps

    .5 to 1 sqft per bird? So with six chickens, we are talking about a 2' x 3' open "block". That sure sounds like a lot of open space to me. I am very interested in this myself, my main venting is one open roof rafter section where the entire side roof profile is open.

    Not finished yet, but in the plans are two window/doors to close off this section that will be hinged in the center. With those figures, it sounds like I will need to leave one of them wide open in the winter. My coop is 6' x 4' with a covered run.


    I had planned to regulate humidity mainly with eve venting (with flaps to close them off, and exit via the ridge vent with a 1" roof gap. Now I am not sure if the four eve vents will be enough??
    Here is a photo of the main vent:
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  5. CityChook

    CityChook Chillin' With My Peeps

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    Minneapolis, MN
    My Coop
    Firefyter - I have been watching your coop with great interest. If I had to do it all over again, it's probably the design I would choose... You've done a lovely job.

    Patandchickens - Oh my, how I appreciate your advice. Buuuuuttttt (don't you hate a big butt???) if I tell him that we'll need to saw through the paneling/insulation/siding to put in vents under the eaves, you just *might* hear the bombs exploding all the way up in Ontario... oh my, what to do... what about this thought - We take out the insulation along the roofline so that the ridge vent and soffits can work properly and then insulate horizontally along the ceiling line (bottom of the trusses) with a large opening in THAT (2x2ish) so that air/heat/moisture can escape that way and go out through the ridge vent? Kind of like a coop attic? We could place that vent closer to the front of the coop (by the door) so to avoid any cold breezes above the roost? Just a thought... I'm trying to build up my case before presentation, can you tell?
     
  6. Firefyter-Emt

    Firefyter-Emt Chillin' With My Peeps

    Well, I think that is a better plan for the roof & insulation, but if you insulate the roof "floor", then you will not be able to release the moist air out of the coop. I suppose you could add some vents in the ceiling, right?
     
  7. patandchickens

    patandchickens Flock Mistress

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    Ontario, Canada
    Quote:LOL - I know exactly what you mean... ;P However he isn't going to be any happier if you tell him that in the middle of a February cold snap when you've got frost forming all over the inside of the coop and maybe chickens coming down with something, either.

    Try researching some Official Numbers for poultry housing to show him?

    what about this thought - We take out the insulation along the roofline so that the ridge vent and soffits can work properly

    That would help. Quite honestly I do not think it would be adequate, though, sorry.

    and then insulate horizontally along the ceiling line (bottom of the trusses) with a large opening in THAT (2x2ish) so that air/heat/moisture can escape that way and go out through the ridge vent? Kind of like a coop attic?

    I fear you will not get very much air exchange in the actual coop this way... less, in fact, than without the false ceiling. The air just isnt' going to move that much on its own, not even from 'heat rising'. You need to encourage a breeze in one side and out t'other.

    I suppose an alternative to peeling back the insulation and gettin' out the Sawzall would be to put in a single, probably gable-end vent (hooded, preferably) and install an outdoor- or workshop-type ventilation fan that you would run most of the time. (Don't use jsut a bathroom or kitchen exhaust fan - the coop dust will toast the fan in short order, and create a fire hazard.) But that honestly sounds like the hard, expensive, inefficient way of doing it, to me.

    Good luck,

    Pat​
     

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