venting question

[imthedude]

hi all

i'm on the tail end of building a new coop and have a ventilation question.

coop is 8x12 with 8' walls in the front and 6' walls in back. i had originally thought i would leave a continuous 2" opening across the top of the fascia board on the front side of the coop, but i've since changed my mind and am now considering some soffit vents or a continously vented soffit panel. with this being a shed roof (only one pitch with high side in front and low side in back), will this be effective ventilation, or do the openings need to be at the highest possible opening in the coop (in my case the top of the fascia board)?

thanks in advance.

 

[patandchickens]

i had originally thought i would leave a continuous 2" opening across the top of the fascia board on the front side of the coop, but i've since changed my mind and am now considering some soffit vents or a continously vented soffit panel.

That actually will not give you any larger amount of venting. Air exchange is limited by the NARROWEST part along its pathway. In the type setup you're describing (if I've understood right) the limiting dimension is the spaces between the rafters atop the wall (typically 3.5" by whatever is the spacing between rafters). You get the same amount of airflow whether you put hardwarecloth on *that* or put hardwarecloth all across the soffits on the outside. Doesn't matter. (Of course, if you put house-style soffit covers on, you are reducing airflow and may well end up with *less* ventilation than if you just had hardwarecloth over the spaces).

As far as amount goes, if your rafters are 2x4's on edge, then the plan you describe in your post will give you roughly 3 square feet of vent opening, total (if it is only on the high long wall. If it is on BOTH long walls, you would have twice that total amount, tho the upwind side might well have to be closed for a while in the winter). This is real minimal for that size coop... if you have a lot lower stocking density of chickens than most people on BYC use, it may be ok in the winter, but it is likely to result in a very very hot coop unless you also have several very large openable windows in summertime, and if you go with this 4 sq ft per hen business the vents atop the wall may not be sufficient for winter either. So you might consider building in more -- perhaps IN the top of the wall(s) -- on the theory that it is a lot easier to do while you're building the coop in the first place than to retrofit some January.

The vents don't really have to be at the absolute highest tippy-top point, btw, just "top of the wall" in general within reason, you know?

Good luck, have fun,

Pat​