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Building a foundation for the Chicken McMansion (Part 1)

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by Chieftain, Dec 31, 2009.

  1. Chieftain

    Chieftain Chillin' With My Peeps

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    The beginning is a very good place to start anything, and building a good foundation is key to any structure surviving the elements. We live very close to the Columbia River gorge, and we frequently get strong winds out of the East that effect anything that stands. We had an enormous tree come down here in the neighborhood on Christmas day due to high winds, so backyard construction has to account for that. In addition, we have had uncounted possoms in our yard over the years, and I spotted a very well fed coyote here in the neighborhood a couple of weeks before Thanksgiving. Add in all of the neighborhood cats, and we really have to consider how to keep unwanted visitors out of the eggs and away from the chickens.

    Our covered coop and run will be 10 feet long and 5 feet wide, with a raised coop that is 5 x 4. What is important is that the roof will be oversized for rain coverage, and the framing will be about 12' x 8' or 96 square feet total. (I plan on using corruguted fiberglass for roofing which needs 12" centers). That is an enormous sail area to present to the wind, and whatever you attach that roofing to had better well be tip-proof, as well as strong enough to carry the load imposed by a high wind, or even a micro-burst in a strong thunderstorm. The forces generated in a strong wind will test any construction that you undertake, so it is wise to overbuild a bit rather than underbuild and lose your entire investment.

    Here is the site we have selected in our back yard. The back fence is East and the darker side fence is South. The structure behind the green bin is my compost pile, and the framing to the right of that is a raspberry trellis. There are two cherry trees in the yard as well. This area has been a flowerbed for several years so the soil is very nice.

    [​IMG]


    I began by excavating about 8" of soft topsoil out of the bed. Then I marked out where the rear wall would be, and laid in several inches of gravel and sand, and compacted it flat and level. You can see I have quite a collection of large river rock that was anchoring the flowerbed, and I saved those for use a little later.

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    It was fairly simple to lay the site out. I need 3' of clearance off of the back fenceline, and I wanted 4' of clearance off of the front of my compost pile. That determined where the first two posts would go, so I laid the lines out with string and nails, and proceeded with a post-hole digger, and dug a couple of good deep holes for the first two posts. I usually stud the end of my posts with galvanized nails, to give the concrete something to grip. The holes were down a good 2 feet and onto solid earth. I set the posts in the holes, and used lath and screws to plumb each post, and hold it straight by attaching them to the fence, the compost pile and each other. Once everything was plumb, square, and on dimention, it was time for a couple of bags of sack-rete.

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    Once you get the first two posts set, and let the concrete cure overnight, then it is a simple matter to come back the next day and set the rest of the posts, and support them where they need to be using the same lath and screws to hold everything in position until the concrete cures.

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    At this point the ground is still pretty soft, so I installed a couple of sheets of ground cover cloth, the gray material in the pictures. I picked a roll of it up at Costco a couple of years ago, and it is great stuff! Weeds absolutely will not come up through it, but water can pass through freely, and that's what we want.

    This next picture shows the pan framing going in. The 4x4 rail is the top rail, and you can see that the site does slope down toward the back. I brought the level of the tamped area I started with up with additional gravel, so that it was 2 4x4's high, and level with the front of the pan which is only 1 4x4 high.

    We have critters here in the neighborhood, so coyotes and possoms getting to the eggs and hens is a real concern, so to prevent anything digging underneath the back (which is most vulnerable) I laid down a length of 1/2" hardware cloth on the ground, with notches cut in it to fit around the posts. Once I laid the back 4x4's in, i bent the inside edge of the hardware cloth up and nailed it to the inside of the timers with a few galvanized roof nails. A coyote would need power equipment to dig through that. The ends are protected the same way, and I laid those river rocks in behind the timbers and on top of the hardware cloth apron.

    I also drilled holes in the bottom 4x4's and spiked the timbers through the hardware cloth apron into the ground with 14" galvanized landscape spikes. Wyle E. Coyote will need a semi-truck full of "Acme" explosives and I still don't think he will get in my coop...

    You can see that the pan will need some fill...

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    So 18 bags of red volcanic stone later, here's what I ended up with:

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    You can see that I filled the pan up to the bottom of the top 4x4 timber, and leveled the entire bed within. I will do some additional leveling, tamp the rock a bit, and add at least a 2" layer of coarse builder's sand over the top of the rock when it's time to move the hens in. Because the entire run will be covered, this pan will dessicate every bit of chicken poop that hits it, and it will be no harder to clean than a catbox. Adding additional sand is a snap.

    Next step will be trimming the posts to length, installing the headers, and roofing the whole structure, then I can get about building the coop out of (most) of the rain.

    More pictures to follow...

    [​IMG]
     
    Last edited: Jan 29, 2010
  2. Ridgerunner

    Ridgerunner Chicken Obsessed

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    Feb 2, 2009
    Northwest Arkansas
    Great documentation and a great job. I understand what you are saying about the wind as a 60 to 70 mph staight line wind took the roof off my shed last May. It lifted the purlins off the rafters. The previous owner had used 2-1/2" smooth nails to attach the purlins to the rafters. When I replaced it, I used 3-1/2" ribbed nails. It will not be coming off.

    I'd strongly suggest you add the hardware cloth apron to the sides and front, not just the back. The back may be the most vulnerable, but at night the critters may not realize that. It does not take a coyote that long to dig under a fence.

    One thing I'd watch for. The ground cover cloth will keep the rocks from disappearing and the rocks will help keep the sand from disappearing. The chickens will scratch holes in the sand down to the rock for dust bathing or just to scratch. If that volcanic rock is the stuff I think it is, it can be sharp. They could scratch or cut their feet on the sharp rocks, leading to bumblefoot. You can do a search on that for more details, but that is where they cut their feet and it gets infected. I'm not going to say you will absolutely have this problem because you may not, but it is certainly something to watch for. Depends on your risk tolerance, but I'd be real tempted to add some smaller smooth gravel to the top of the volcanic rock or even replace the volcanic rock with smooth gravel. Maybe adding a 2 x 4 on top of your sills to hold the extra gravel in?
     
  3. LynneP

    LynneP Chillin' With My Peeps

    I'm very happy to see that you protected the base with hardware cloth. Did you extend under the entire base to prevent tunnelling? It looks like 1/2" gauge and you'll be happy with that. Keep in mind that over the years even with a galvanized finish, that the wet climate in your region will eventually corrode it, though it won't happen soon. As you continue, look for other applications of this material. I know what you're saying about high winds- we're in a hilly zone and we get hurricanes and blizzards that curl the toes and leave one cringing before morning light. I have some links below that may be of some help,lots of pics and construction ideas. Not that you should worry about winters like ours! Nicely done...[​IMG]
     
    Last edited: Jan 1, 2010
  4. TeamChaos

    TeamChaos Chillin' With My Peeps

    Nov 8, 2009
    Wow, what a beautiful and well-explained post, awesome!
     
  5. Chieftain

    Chieftain Chillin' With My Peeps

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    Dec 21, 2009
    Whew! It's been over a week since I was here and believe me it's because I have been busy, and not just with the coop.

    Thanks Ridgerunner, thanks for the advice! I did add hardware cloth all around, and you're exactly right that it doesn't take a determined critter to dig under a foundation. I will be adding another fir 2x4 plate on top of the 4x4 timbers, which will enable me to put in a lot of sand and give me a nailer for the hardware. I know what you mean about the rock, but I think the sand bed will be deep enough that the chickens won't be able to excavate that deep. I will keep an eye on that, thanks!

    By the way, KGW.com is the website for one of the local Portland Oregon television stations, and if you go over there, they still have video up from yesterday, where one of their correspondents was out in the Columbia River gorge where there where 100 MPH winds, sustained. They were at Crown Point which is a narrow spot in the gorge, and the winds through there are legendary. Here at the house we had gusts over 50 all day and the new roof never budged.

    Instead of expanding this thread, I will start a different one to show exactly what I did for a roof, but here's a peek...

    My wife is calling it the "Coop Deville"....

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