Thursday, March 17, 2011


Ed was correct in his assumption that I would be pouring concrete soon. This is the formwork for the future chicken coop. Or the Taj MaCoop, as Woody put it. Now, I know some of you are looking at this and thinking, that's a helluva thick slab for a chicken coop. Well, it's not so much. See, none of my land is flat. None. Not 10 square feet anywhere. It's all gently rolling hills or steep inclines. I picked the flattest part I could find around the garden but it still meant a 12 inch elevation change in 12 feet. But, that is easily remedied with a concrete slab.
I wanted it connected to the garden for a variety of reasons. At certain times, when there are no tomatoes, the chickens can be let right into the garden to patrol for bugs etc. Scraps from the garden are easily thrown to the chickens and chicken poop is easily gathered and taken over to the garden. Plus, I already have electricity and water at the garden and it won't take much to trench the power down to the coop, although I would like to maybe install some solar lights. And, last but not least, I already have shock wire run around the garden and it won't take much to incorporate the coop with this. The coop will also be known as ChickenTraz.

So, forming the slab here wasn't much problem but I did have to fill the interior in order to have only a 3 inch thick slab to pour. This involved wheelbarrowing a lot of dirt and gravel but that's good exercise. However, if you do this, you MUST tamp the fill so that it won't collapse on you later and have your slab crack. And that dirt will settle, I assure you. So, that is what this contraption is above; a motorized tamp. One of those little handle doolollies ain't going to do it. These big tamps are way cool. Due to Allen and I being in the business, we just happen to have one residing here all the time. It doesn't get a lot of use but is very handy to have. The things are extremely heavy, as you might guess, and when running that thick plate on the bottom vibrates, causing the tamp to well, tamp, and actually move forward. You can barely pull one of these things but when running it moves along on it's on.

It's kinda hard to see in this photo but I left a small turndown around the perimeter of the slab for a footing. You must have this so that the edge of the concrete turns down to contact undisturbed earth. This is kind of a mini version of what we call a monolithic slab. Meaning the slab and footing are poured at the same time. My little footing turndown is only about 5-6 inches wide at the bottom.

I dug the right hand side down just as low as I could, and still have the slab be above grade but that still gave me about 11 inches on the other end. The slab is 12'x8' and it slopes 1/4" per foot in the short direction. This is to allow drainage when I hose the slab off for cleaning. I know most people would not go to the trouble of pouring concrete just for a chicken coop but I have my reasons. 1. I am just partial to concrete; it lasts. You will never have to redo it. 2. No predators will be allowed access to my chickens. They are for my meals, not theirs and I prefer not to kill predators. I think it is better to just not allow them the opportunity. 3. Concrete is easily cleaned and a clean coop is essential. 4. With the rising cost of lumber, concrete is a good deal. The local batch plant used to charge an outrageous minimum on concrete; 5 yards. I suspected with the recent falling economy that maybe they haven't been doing as much business and might have changed their policy. I called them and what do you know? they said they would work me a deal for just 2 yards. How about that? If I have decided to floor the coop in plywood I would have to use pressure treated, probably 3/4 inch, and it would have cost about what 1 yard of concrete is going to run me. With 2 yards, I can also pour a small footing for the tool shed I want to build connected to the coop.
So, I'll be back later to show how I finished my preps for pouring this slab. Oh, and I meant to say I did not buy any lumber to do the formwork. It was all constructed of scrap material I had laying around. Basically just old 2x4's and stuff. Unless it is going to be pretty architectural concrete that is really going to show, I almost never buy form material.


Ed said...

Although it is an additional cost when you have free dirt and rock around, we use sand as a fill material which works great and doesn't need tamped.

I love your assessment of concrete but don't forget there is a significant thermal mass that will come in handy for them chickens during the summer and winter months. Those reasons and all the reasons you mentioned are why I want to build my dream house completely out of concrete and closed cell poly foam.

vlad said...

Useful info here.

edifice rex said...

Hey Ed! Sand? I've never seen that done. Great to know that works though!
You are correct also about the thermal mass aspect; I didn't even think about that. ha! yes, I've read about that poly foam/concrete. It seems very efficient.

Hey Vlad! thanks so much for that link. It is some very useful and interesting info there. I had never thought of the hedge idea but I have been contemplating a pond or retaining pool for raising fish or shrimp. Good to have you here!

Ed said...

Sand works great with the caveat that I forgot to mention that you need to put it on undisturbed soil for the reasons you said in your post. We just spread it, screed it off to height and pour the concrete. Left over sand also makes a great sandbox when paired with a tractor tire, or at least my daughter thinks so when visiting my parents farm after a grain bin pad pour a few years back.

edifice rex said...

Hey Ed! lol! I guess it would!