Lean-to style coop?


9 Years
Feb 26, 2011
We are planning to build a "lean-to" style coop attached to the side of our current garden shed. It would be on the same concrete slab. Is there any reason not to build a coop onto an existing building or slab?
Welcome to the forum!

No, I would say it's great to use what you have as long as there are no existing problems (like drainage) with it. You will want to put some kind of bedding down (shavings, etc.) on top of the concrete to make it usable for a coop.
I'm also interested in the lean-to design.
(WholeHearted) How hard is your winters there....?
I'm wondering about cold & concrete??
Jim Brown
Lockport NY
We are in NE Ohio, so winters can get very cold. This year seems especially bad.

In my research on this site, I thought I had read that concrete had a high thermal mass and was a good choice for taking advantage of latent heat. I could be totally remembering that wrong though. Our other choice would be a freestanding shed with wood flooring. I thought that might be more prone to drafts as well as predators. I had also hoped that a deep litter method of bedding on top of the concrete would provide a barrier and source of warmth. Also, is there concern with moisture when using concrete and/or do we need to specially seal the concrete in some way if we go with this?
Hopefully someone who has actual experience with a coop like this will be able to give you some good advice.

I have been thinking about this for myself when I build my coop in the future - no chickens yet at my house. We have terribly windy winters, are limited by HOA coveneants to only two auxillary buildings and already have plans for a storage shed and a detached garage. I am thinking that building my coop as a lean-to on the shed would help protect it from from the wind and covenants.

My question is this: If the back wall is not an exterior wall, but a common wall with an unheated shed, will there be moisture issues with the original shed wall? ie. will the moisture from the chickens condence on the common wall and start to mold or rot the wall?
and should I make sure that the shared wall is covered with plastic to prevent moisture from building up in it?

Typing this up makes me think that making sure that there is enough ventilation -without drafts - would be the biggest benefit to preventing moisture issues. I think I will still seal the common wall with plastic and painted plywood to try and keep chicken dander, dust and mites from migrating through any gaps in the wall and into the shed area, plus it will close of any spacing under the siding where the mites could hide and live.
Just had to comment and say hi neighbor. You are the first person I have seen on here from our area. I live in Wilson.

My coop is built on a concrete slab but has 4 sides. I would suggest maybe some basement waterproofing paint on the slab. One thing I can say is that when its hot in the summer they like to dig all their bedding off to the side and lay on the cool concrete. I am having issues with mine right now because its old and it cracked and now during the spring it floods. So this summer I have to fix that.
The common wall could be insulated on the shed side, thereby greatly reducing condensation.
concerning concrete floors two things come to mind. 1. Heat rises, and cold settles. 2. using the deep litter method, maybe only in the winter, will practically eliminate cold transfer. An extra step that one might take is berme up around the edges of the coop. (Only necessary in the winter.) A "curb" of hay or dirt or even snow(which is always 32 degrees) around the perimeter will help reduce cold transfer. If the "curb" becomes wet it will freeze and all good intentions are for naught. One might use scrap plywood or tar paper or possibly plastic sheetingas a waterproof cover. As an example you may have heard; "rake leaves up around rose bushes to help protect them", if the leaves become wet and then freeze you have created a condition worse than having done nothing at all. However if one were to put the leaves (or in my case, sawdust) in a stout garbage bag, the result is ... "bagged insulation"! Just make sure the bags don't blow away when they're needed most.
Very helpful thoughts about insulation and condensation. I hadn't thought of the berm/curb idea, but it makes a lot of sense. We don't have any pics of what we'll be doing, but dh is just going to adapt a shed plan that has a roof only slanting one direction. He'll improvise from there. Should be interesting. I will post pics once we get to that point!
Uh, snow is NOT "always 32 degrees", not by any means. It can get just as cold as the air does. (e.t.a. - perhaps you were thinking of ice-water, of which that IS true?) Because of its high air content though snow is still a good insulator even when it is pretty darn cold. So yes, piling it up against the sides of the coop does provide some insulation (until and unless you get an air gap developing between snow and wall, anyhow, which tends to happen)

Bagged leaves are also useful but can farm up rodents so should be used with thought and observation.

None of this is highly relevant to a slab though (as opposed to concrete or cinderblock kneewalls)... it makes a *little* difference if you insulate around the edges but really not *much* and there are far more useful things to worry about IMHO.

There is no reason not to build onto the existing slab, slab is a GREAT coop flooring. Just bed it real deep with fluffy shavings or fluffy straw in wintertime is all, and it works wonderfully. It is best to not leave any slab sticking out beyond the walls of the building -- i.e. try to use the WHOLE remainder of the slab for your coop -- because otherwise it can be hard/unreliable keeping rainwater that pools on the exposed slab from tracking into the coop underneath the walls. You may not have noticed this in your existing shed but you would sure notice (and care!) if it happened in a coop, as it'd result in damp bedding and frostbite type problems. There are things you can put under the sill to try to seal it but they do not always succeed so it's really better to try to avoid the situation in your design.

Good luck, have fun,

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