I am taking a brief break from my usual woodworking pursuits to build a chicken coop. In my earlier post, I cleared an area of land of trees and detritus and raked it as level as I could. I couldn’t get it as level as I would have liked due to the natural fall in the land. Because of this, I will have to make a split level foundation. You can read the first post here:
I decided to use a cement footer as the foundation for my coop. When I built my barn/shed, I used pre-made concrete piers (pyramids) with galvanized saddles for a 4×8 beam. However, Home Depot had 60 lb. bags of concrete mix on sale for $1.98, and I figured that I could make a full concrete footer for less than the cost of the pyramids and pressure treated beams. Also, having a full concrete footer will be much more secure and prevent predators from digging under the bottom of the coop.
To make the concrete footers, I first needed to needed to build forms. I bought a few sheets of Oriented Strand Board (OSB) and ripped them into 6-inch strips to build the forms. I designed and built the forms to fit the available space on the land rather than having a pre-planned floor plan. This meant that the outdoor chicken run didn’t form a L-shape at a standard 90° angle, but instead joined at 113°. This will make framing and roofing a little more challenging in the later stages, but I would rather build a structure that maximizes the available space. The inner and outer forms are held 6-inches apart with metal spreader cleats, resulting in a 6×6 footer. I built the forms on the “somewhat” leveled land, left it loose.
My neighbor across the street is a contractor and came over with his laser level to help me level the forms and stake them in place. To get it level, I had to lift the longest wall up by about two inches. This means my concrete calculations are going to be thrown off and more concrete will be needed. Once the forms were leveled an staked in place, I had to add some scrap wood at the bottom in a few places to hold the concrete in. I also mounded up dirt along the outside of the bottom of the forms.
Next, I decided to add some re-bar to the foundation. On such a small footer, I’m not sure how much strength this is going to add or if it is really needed, but re-bar is pretty cheap and I didn’t need a lot.
I bought 50 bags of concrete and got ready for a long day of mixing. I have a small cement mixer that can handle two bags at a time which isn’t a lot, but it sure beats mixing by hand in a wheel barrow. I mixed and poured all the concrete for the lower form on the first day. I realized that I wasn’t going to have enough concrete and went back for another 10 bags the next morning. On the second day, I continued on and mixed and poured all of the cement for the upper section.
In the end, I used 59 bags of concrete (60 bags equals a full cubic yard).
Just as I was finishing the upper pour, it started to rain. No rain for months, and the day I pour concrete it pisses down! I managed to cover it up with some plastic sheeting.
After removing the forms, I raked the area and cleaned things up a little.
Inside the foundation, will be 3-inches of gravel, and later, once everything else is done, 3-inches of sand on top of that.
My utility trailer came in very handy for hauling loads of gravel. It can only handle about ¾ of a yard of gravel at a time, it doesn’t look or sound like much, but that much gravel weighs one ton. I’ve hauled about six loads so far and will probably need one or two more before I finish up.
My projects often morph into something larger than originally intended and this one didn’t fail to follow that pattern. I decided that the L-shaped style of the coop left an area that would be great for building a firewood storage shed. Since I still had forms, I cut and adjusted them to make a second concrete footer. I figured that I might as well do it now since OSB doesn’t hold up to well to moisture and the forms may be unusable later.
The second form was leveled with my neighbor’s assistance once more, and I mixed and poured another 28 bags of concrete.
I also had to do something about the rock wall in front of the coop. Originally the wall was curved and was too close to the foundation. I removed the rocks and installed some preformed concrete steps. I then rebuilt the rock wall and back-filled it with gravel.
Its been a long, slow, slog so far, but I’m finally at the point where I can start working with wood again. I took the trailer to the lumber yard and bought all the 2×6’s that I will need to build the floors for both the hen-house and the woodshed.
In the next post, I’ll start all the framing.
More soon.
– Jonathan White
I can see from the pics that you didn’t forget to put the J bolts in. That will make attaching the sill easier and if tied into the rebar will make the rebar worth doing..
Hey Ralph,
Yep, that’s what I thought too.
Jonathan
That rock wall is awesome. Great build photos, by the way.
Thanks Ethan
This chicken palace and resort building is awesome. Thanks for sharing.
No idea how to go about any of this, so please excuse the naivety: Why do you need to go through all the fuss with the leveling? Couldn’t you just pour the concrete to say 85% and let gravity do the leveling? Isn’t it that liquid?
Yes, I build software not houses. Now you know why 😉
Hi Mariano,
Thanks for your comments. Leveling the forms is an important step. The key thing is that the tops of the forms be level, the ground level and the bottom of the form are irrelevant (other than how much concrete it will take to fill it). When you pour the cement, you fill the forms to the top and then smooth it all out. Therefore the top of the form becomes the baseline of your building. If it is not level, then any building that you put on top of the foundation won’t be level either.
Concrete is “liquid” when you pour it, but it is much thicker that you might think. It won’t really self-level. In fact, you can easily pour concrete that is deliberately not level. I’m sure you’ve seen concrete driveways that go up or down a hill.
This stuff, I can wrap my head around. However, trying to design software would have me baffled. My hat’s off to you!
All the best,
Jonathan
Your build looks amazing and is a real inspiration. I’m also in WA and starting on my own coop. With this foundation do you have to worry at all about frost heave or do you expect it will float as one unit?
Ummmmmm… Reading your comment is actually the first time I even considered frost heave. You know that sinking feeling you sometimes get…
So based upon this, I’m going you say that it will all float as one unit. I hope.
Where in Washington are you? In in coastal western Washington and we don’t generally get too severe a freeze here.
I’m in the Seattle area. I’m probably way overthinking this for a chicken coop.. and really don’t want to dig/pour down to the frost line. So, I’m inclined to agree with you.