Or how not to build a catenary curve chicken coop.
Back in 2007 I rescued 7 baby chicks from a cull of feral chickens in a local park. I eventually built them a large A-frame coop-and-run, but as they were mostly free-range in our back yard (and more often than not in the front yard), even back then I had plans for a smaller, more easily movable "night-coop" to sit inside a proper run.
The coop needed to be dog-proof, for when it was used in the vege garden, and dark enough so the chooks would not wake too early and disturb the neighbours. It only needed to be big enough for about 8-10 chooks to sleep in, as the coop would be attached to a large run.

As a fan of curved architecture, I chose to build based on a catenary curve. Here's how I attempted it. You will want to learn from my mistakes...

I had thought I'd come up with a new concept, what with finding nothing on the Web, but after starting construction I found a very similar design. Typical! This appears to be the entire living quarters though, whereas mine is only the bedroom.
This one deserves mention also.

Step 1: Establish a catenary curve

A catenary curve is the shape made by a chain hanging from two points. This is distinct from a parabola. Freely-formed honeycomb takes a catenary curve apparently. As I wanted a coop 1m wide* with a curve of 2.4m**, I figured there would be an online equation for a catenary curve such that I could calculate the coop height. Well there is***, but I can't make head or tail of it. There is a simple version I'm sure, but I can't find it!
Well, duh. After much web surfing and learning more about curves than I thought possible, and after actually building most of the coop, I came up with the brilliant idea of tracing the shape of a 2.4m length of chain nailed to ply. By measuring 400mm down the centre-line from the base, I could then square-off the curve with a couple of nails/screws to allow for a wider shape.
If I was to do this again, I'd use this technique to cut two full ends (using the first end as a template for the other panel) and bend the ply over them (much like building a boat hull, but see what happened in the next step...).

*(to fit on my garden beds)
**(NZ ply is 1.2 x 2.4m; equivalent to a sheet of 4 x 8ft)
*** http://en.wikipedia.org/wiki/Catenary and http://curvebank.calstatela.edu/catenary/catenary.htm
I showed my wife the pic on Step 10 (the 17 chickens roosting on their ladder). She said "Awesome - that's exactly what I want for our coop". Nicely done Instructable. I liked the "bird's eye view."
<p>I know this is four years later, Streetrod5, but you may like this idea from Mother Earth News:</p><p></p>
Glad I could help! (with credit to the photographer). Yeah, the &quot;bird's eye view&quot; is cool, but I thought chickens had better focus than that...
THIS IS AWESOME I'm so gonna build one for my chickens and maybe even as a kennel for my dog!!!<br/>Kirin
Thanks Kirin! That makes all the hard work writing this 'ible worth it. As I've said else where, you'll find it a lot easier if you:<br> 1. Use nice flat sheets of ply for the roof and ends<br> 2. Cut the ends using a template. If you want the gothic arch rather than the catenary arch, you could scale up the method I used for the pop-hole, making sure that the total perimeter was the length of a sheet of 3-ply<br> 3. For the gothic arch effect, cut the 3-ply in half as I eventually had to in Step 2, align the grain as I did in Step 3, and &quot;wrap&quot; the 3-ply over the 12mm 7-ply ends, attaching it as in Step 8.<br> 4. Use a strip of flashing along the roof peak, or seal it well with silicone. The attached picture shows what I mean.<br> <br> To avoid using the corrugated roofing, I'd inset the end walls about, say, 100-150mm so the roof overhang is better. There is no reason why the back wall can't be solid and sealed, in which case it could be flush with the edge of the roof rather than inset.
Thank you so much for sharing this cute Gothic idea!
<p>Thanks <a href="http://www.instructables.com/member/lcourville" rel="nofollow">lcourville</a>! Curves always look better than straight lines, I always say.</p>
Here's an inset wall example from The Log Pod, but you wouldn't go <em>quite </em>so far in.
I'm just curious on how this is gothic.
Fair enough sofia. A gothic arch is a peaked arch - an ogive. In Step 3 I described how the construction method &quot;... formed more of a gothic arch than the catenary curve I was hoping for.&quot; The construction of the pop-hole is an ogive, although I didn't know at the time that was what I was doing! Here are a couple of wiki articles:<br> <a href="http://en.wikipedia.org/wiki/Gothic_architecture" rel="nofollow">http://en.wikipedia.org/wiki/Gothic_architecture</a><br> <a href="http://en.wikipedia.org/wiki/Ogive" rel="nofollow">http://en.wikipedia.org/wiki/Ogive</a>
But you didn't need to know all that about arches did you? My wife always says I give too much info - I have no idea what she means...
That's what I was suspecting but my wife is &quot;goth&quot; &amp; she wanted some clairifacation on it lol. For my two cents I'd have put on a faux stone coating on it &amp; it would be taken up a few thousand notches but that's just me.
Yeah, stone would be great - oooh! and little chicken gargoyles! :] . I am sorry your wife was disappointed: these pics are the best I could do in that theme (dunno if those women qualify as goths, but they are holding a chicken).<br> See these sketches also:&nbsp;<a href="http://whyarchitectsdrink.blogspot.co.nz/2009/04/myrtle-mae-monday-041309-yet-another.html" rel="nofollow">High Gothic cathedral/coop</a>
Those are awesome pics, I love the gargoyle idea. I think you know what you need to do for your nexy project lol.
Your wife has a peaked arch? Okay!
I would make a comment but there are those on this site that aren't old enough for that kind of humor.
No doubt you've worked really hard and the result is awesome! wish I could make one, but it'll take me years!
I did work hard on this Muhaiminah! I glad you like the results. It wouldn't take you long if you use my hindsight suggestions of precutting the end walls from a template and perhaps kerfing the roof ply so one uncut sheet will bend right over the whole structure. Heck, you possibly wouldn't even need the base frame, although the thinner ply might be a bit flexy without a 50x50mm rail along both sides.
The final result looks good and it seems like you've learned a lot along the way, which is always a good result. <br> <br>Thanks for sharing your project.
Thanks DD. I like your philosophy, and there certainly are several things I'd do differently. Next time, with what I know now, I'll be able to make a <em>catenary </em>coop in a day I reckon. I'd probably do a bigger overhang with the thin ply and not have the corrugated plastic at all.

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