Existing Slab Coop Options

[KirbyCoop]

Hi everyone, this is my first time posting here.

My wife and I have been planning on adding a chicken coop to our yard here in Fallbrook, CA (north San Diego county). There is a preexisting 12' x 20' x 3.5" concrete slab where we plan on building it. I don't plan on utilizing all of this space for the coop/run since we need some space to walk around it and to allow for diverting any runoff (not that there is much here in SoCal). So, I have drawn up plans for a 8'x20' total footprint. 8' x 8' for the coop and the remaining 8'x12' for the run.

The fenceposts lying across the slab here are just to show how out of level the slab is (they are roughly level)

My plan was to cut the slab down to the 8' x 20' footprint and dispose of the remainder. French drains would be added around the remaining slab to prevent any runoff from flowing on top. There are some structural/foundational questions I'm still working through since the pad is relatively thin, needs a few spots repaired, and slopes about 1/2" per foot (a full 10" lower in the back left corner). But the main things I was hoping to address here is whether I should bother utilizing the pad at all. I initially thought it would be useful for pest control, but I'm beginning to think it may be more trouble than its worth. The significant slope would require that the coop have a raised wood subfloor anyway. For the run I imagined 6" or so of bedding on top of the pad. I'd like to minimize future maintenance and smell as much as possible. I'd like some input from you all before making the decision to invest in using the slab or tearing it all out.

As far as chickens we don't plan on having any more than 10, and all bantams (a mix of silkies, polish, and sebright are on our shortlist).

Any advice would be greatly appreciated. Obviously there is a lot more to figure out here, but the foundation feels like a logical point to start.

Thank you,
Michael

 

[cavemanrich]

We each have different visions as to how to complete this. This is just my opinion, and how I would do it. I am of course no standing inside your yard, to get the full effect.
Leave the slab in place. You can saw off 4 feet of the width of slab, or just leave as is. Build the structure level at roof line, but utilize the slope to your advantage. This means that the studs would be slightly longer on low side,,,,, and slightly shorter on high side. This way you can easily hose down the interior of coop, when cleaning. Water drains out the back. (I can give you tips on providing a drain-able wall bottom.) Place layer of bedding on cement floor,, and good to go.
In front where the natural height occurs, Run area,, you don't need such deep amount of bedding. You can use sand, and 2 inches works just fine for chickens to scratch around in. I would use sand for total run space myself.
You can make a small curb against the coop,, to hold in the sand in run,,,, and divert/prevent rainwater flowing into coop.
Ask more questions to clarify what may be confusing, or not clear.

WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,and

 

[saysfaa]

In your climate, four walls for the coop are going to cause a lot more problems than they solve. They will hold the heat.

Have you considered an open air coop? Basically, it is a roof (for shade mostly, and the rare rain), one solid side (for wind protection mostly, also for rain protection), hardware cloth for the other sides (for predator protection). Or one solid side (the back) and two feet or so on each side. I would make the solid walls solid for only about two feet, raised up to shelter just the roost. Oh, and the nest boxes could use shelter if they don't have solid walls and roof.

I would also keep the concrete under it. I would not pour concrete for a coop because it isn't worth the cost and effort. But it is worth using if you have it and, besides, will save you the work of removing it and the difficulties of disposing of it. I would put a hardware cloth apron out from it to keep pests (like rodents) from digging under it.

I don't see any reason not to use the thick bedding you describe. I would build a short wall of some sort to hold the bedding in place. Possibly a couple of sort walls across the middle because the litter will migrate downslope. It could be just a 4x4 or 2x4. Lol, and the chickens love to stand on walls like that.

The chickens won't care if the floor slopes. Why do you think you need a wooden floor?

 

[KirbyCoop]

Thank you both for your responses.

My reasoning behind the wooden subfloor was more avoid the framing complications of shorter-to-longer studs in the walls (non-square), but if everyone thinks concrete base in the coop as well is good then I can go with that. @cavemanrich I would love to hear your tips on making the bottom of the wall drainable.

@saysfaa My hope was that a combination of open eaves and a continuous ridge vent would provide adequate ventilation for the closed in coop (and maybe a radiant barrier for the roof). I was also planning on adding some windows that could be left open during the hotter parts of the year. For cold weather, there is never snow of course where I am, but we have maybe a few months out of the year where it gets in the mid 30's to 40' (Fahrenheit) at night. If you think its still a bad idea then please let me know; convincing the wife might be a challenge aesthetically.

Would the actual deep liter method work on top of the pad, or would that be out of the question?

 

[cavemanrich]

My reasoning behind the wooden subfloor was more avoid the framing complications of shorter-to-longer studs in the walls (non-square),

Another brainstorm crossed my mind with solution. Will simplify framing very much.
Mark out the perimeter of the coop portion on the concrete slab. Frame out a narrow curb style foundation on top. Needs to be only width of 2 x 4 stud, 3½ inches wide. On the high side,, there would be no curb,, on the low side,,, whatever makes for a level foundation. Into the low side curb,, place short pieces of pvc pipes on the very bottom. I suggest small size like 3/4 inch should work well.

I just grabbed a random picture to convey my idea. The blue and red circles show where to place the short pipes. This would be your low end side.

You can do one 8 foot section at a time. Start from where it is high,,, and gets no cement,, to the lower end,, where you fill up to level height. Probably would not take very much cement,, and mix it up in a pail a little at time. Remember that the finished curb does not need to be perfect. A 1 inch difference would not make a visible difference in sight.
Since you are making a very small curb,, I suggest you get Masonry mix, instead of concrete mix. Concrete mix contains stones up to 3/4 inch diameter. Harder to work with making thin layers. Other option is a bag of Portland cement, and mix with your own sand. 4 to 1 ratio will work just fine.
If you choose to go this route,, suggest you place a few bolts into the liquid concrete to hold you framed wall in place.