How does roof type affect humidity in the coop?

[gtaus]

For the past 2 weeks, I have been observing the temp and humidity inside my coop compared to outside temp and humidity, and so far I have noticed that my coop is about +5F warmer than outside air and about 8% less humid. To give some reference on my setup, I built a 6X12 coop with a gambrel roof on an old boat trailer. The idea was to make the coop easy to move. I have 10 hens, so almost 8 square feet per bird, because I expected they would stay inside the coop most of the winter, and that is what they are doing.

Anyway, here is a picture of the backside (working side) of the coop where I have the feeder and heated waterer inside the big doors. You will notice the vent towards the top of the roof. There is another vent of the same size on the front side of the coop. Those vents are left open all the time.

The main part of the coop is about 6 feet high, and the gambrel roof is about 9 feet high at the peak.

Here is an old side view of the coop where you can see the sliding window above the unfinished (at that time) nest box access panel. There is another same sized window on the other side. Those windows are cracked open all the time.

Some of the constructive comments I got from the BYC community was that I did not have enough ventilation. This is my first winter, and I decided to monitor the temp and humidity in the coop. At this point, I don't see any need to add ventilation if my inside coop humidity is less than the outside humidity. I am thinking my gambrel roof design with vents on both the front and the back, even though they are small, are more than adequate (for my 10 hens) due to the large volume of air contained in the gambrel roof design above the roosts of my chickens.

My question: Is the gambrel roof design inherently better for venting humidity than other roof designs, or is it just that I have only 10 hens in a coop (8 square feet per bird) that could probably handle 20 hens (4 square feet per bird)? If I had built a conventional gable roof of the same size, would the humidity inside the coop be more/less?

I ask because I have been considering building another shed that could double as a chicken coop if needed. The gambrel roof is more complicated to build than a conventional gable roof, but maybe the design of the gambrel roof just has more advantages. Thanks for any thoughts.

 

[Ridgerunner]

Jut some opinions, no real definitive answers. I think your low chicken density really helps, as usual more room is better. The dry bedding absorbs the moisture. Wet poop is a problem, dry poop generally isn't. What causes poop to smell is the bugs breaking it down. If it is really dry those bugs can't live and reproduce. If it is damp those bugs are aerobic and you get a nice earthy smell. If it is too wet for oxygen to get to them, you get anaerobic bugs that stink and produce ammonia. Yours is obviously dry enough.

Frozen poop will not break down so it won't smell, but when it thaws it can be wet if clumped together. Instead of turning it in the bedding you might be better off trying to remove most of that iceberg from the coop. The thaw is when it could cause problems.

I'd think as long as the vents were the same size and in the same spots, plus those windows cracked, roof shape wouldn't make that much, if any, difference. If your chickens are not getting frostbite what you are doing is working. I hate these magic numbers we throw out as rules of thumb. For many of us they are overkill, but in some cases not quite enough. We are all so different in our conditions.

I personally would like more ventilation and I like simplicity. If I were building your new one only six feet wide I'd use a single sloped roof, about as simple as you can get. And with enough overhang to leave the top of both the short and high wall open, covered with hardware cloth for predator protection, to get all kinds of ventilation. Just keep the roosts low so a cross wind does not hit them. But many people would not find that attractive enough.

 

[RoosterML]

While the humidity may not be bad keep in mind that making the vents larger will really help in the amount of air exchanges you get. BUT if humidity is good and your coop passes a scientific sniff test I don’t see any reason to change it. If it ain’t broke , you know the rest.

 

[gtaus]

IMO a gambrel roof is not an advantage but a detriment due to no soffits.

Excellent point and one that I considered in my design. A conventional gable roof does have soffits, and it easier to build. But the gambrel roof has much more air volume and in a shed can be used for more storage in a loft. My chicken coop is the first gambrel style roof I have ever built, but it seems to be working out well for me. I am wondering if the lack of soffits in the gambrel style roof is overcome by the increased air volume and vents at the roof peak? I really don't know.

Many things contribute to humidity levels inside a coop. Is the 8% difference consistent all day long? What is the ambient humidity outside? I assume you open that big access door daily? And I think you have deep dry shavings as coop bedding?

The remote sensor I have inside the coop is almost always about 8% less humid than the remote sensor I have outside the coop. And my coop is almost always about +5F warmer than the outside temp. Today might be a typical day with temp at 17F and humidity of 87% outside - it's a gray foggy day today.

I do open the big access door daily, once in the morning when I open the pop door and check the food and water, and again at night when I close the pop door and count the birds before I lock up everything. Those doors are not open more than maybe 5 minutes total per day.

I do have deep dry shaving as coop bedding and have been amazed at how well it is working for me. For many weeks I was commenting on how the chicken poo under the roosts was being turned over by the chickens and magically vanishing into the litter. Well, not anymore. The nights have gotten down to -22F and the chicken poo under the roost is accumulating like a frozen turd iceberg. So I will have to go in there this weekend and see if I can turn any of the frozen poo over into the bedding and/or I'll have to throw some more wood chips on top of the frozen poo. Other than that, the rest of the coop with wood chips is dry and there is still no smell. Maybe frozen poo has no smell?

Pretty hard to assess all the factors and come to a gross conclusion about roof type after just 6 months or so of use.

Yes, I know that, but I have not seen any discussions on roof type advantages/disadvantages for chicken coops. Maybe someone has good info on this subject, or maybe just antidotal experiences to talk about. As I said, I am thinking about building another shed/chicken coop ready structure for next summer.

Thread should spark some interesting discussion

I hope so, but as always, I appreciate your reponses. Thanks.

 

[aart]

IMO a gambrel roof is not an advantage but a detriment due to no soffits.

Many things contribute to humidity levels inside a coop.
Is the 8% difference consistent all day long?
What is the ambient humidity outside?
I assume you open that big access door daily?
And I think you have deep dry shavings as coop bedding?

Pretty hard to assess all the factors and come to a gross conclusion about roof type after just 6 months or so of use.

Thread should spark some interesting discussion

 

[aart]

Today might be a typical day with temp at 17F and humidity of 87% outside

That's pretty darn humid at that temp!!
Wonders if you tested your hygrometers for accuracy, easy to do with the salt slurry in a bag method.

Not all gable roofs have soffits, a lot of sheds do not,
only those thoughtfully build to hae overhangs

I'm sure the large volume of your high roof helps.
If I ever had to build or repair a gambrel roof, I'd go this route.

 

[gtaus]

That's pretty darn humid at that temp!!
Wonders if you tested your hygrometers for accuracy, easy to do with the salt slurry in a bag method.

I double checked my remote sensors with the official weather station at our local airport. Not much difference. Again, it's a very gray and foggy winter day which is why the humidity outside is so high.

I never heard of salt slurry test, I'll have to look that up. Again, I have just double checked my remote sensors and compared them to the official weather station a few miles down the road at the airport. They have been close enough in the past so as not to cause me any concern on accuracy.

 

[gtaus]

BUT if humidity is good and your coop passes a scientific sniff test I don’t see any reason to change it. If it ain’t broke , you know the rest.

Yes, my highly accurate and time tested sniff monitor is still fully functional. "The smell will tell" is a motto that I have used for many years when keeping small animals.

 

[gtaus]

I personally would like more ventilation and I like simplicity. If I were building your new one only six feet wide I'd use a single sloped roof, about as simple as you can get. And with enough overhang to leave the top of both the short and high wall open, covered with hardware cloth for predator protection, to get all kinds of ventilation. Just keep the roosts low so a cross wind does not hit them. But many people would not find that attractive enough.

I considered some designs like that, but I was really influenced by the Carolina Coop designs I watched on YouTube and built my coop around the dry deep litter needs. Also, I wanted to build something that looked like a small barn in the backyard. My neighbors watched me build the coop on the boat trailer frame and many complimented me on how well it turned out.

It could be that the neighbors were just being nice to an old man, but even Dear Wife told me that the coop turned out much better than she thought it would. And Dear Wife can be brutally honest when she wants...

 

[DiYMama540]

I'm not one to be able to talk specs of coop building...just wanted to say, nice looking coop! The idea of building it on a boat trailer is great!