Coop design advice needed

Hi everyone.

I've tried searching for this info but there are just so many results and most don't come to answering the exact issues I want to try to get clarified, so I hope you don't mind me asking here. If there are any relevant threads, please do post them here if that is easier.
Also, if there is a guide that covers all aspects of coop design then I haven't found it and would love the link to that instead.

With that said...

I'm planning a coop that is 8'x4' with a 8'x12' run - the idea was to be most efficient with the materials sizes and we have enough space to allocate for it, so why not? My design is based on a number of coop plans I've seen here as well as on YouTube but I've noticed that many of the plans don't go into specific measurements (that I've been interested in at least), which is a shame because this is really my first project that I will be building from scratch and I could use all the help I can get,


I'm planning a lean-to roof with 1 foot overhang at the front (8' height) and 6" overhang at the back (6' height) with a gutter to collect rainwater in a barrel. I don't plan on going up on the roof once it's finished and was wondering about spacing the rafters. I've read that they should be at most 24" apart regardless of size (2x4 or 2x6) but seen many designs were it seems like they are pretty spaced out. Considering we get snow here in winter, maybe I should stick with 24" or even consider 16" or somewhere in between?

I am also pretty confused about what to put on the roof - I was just going to put plywood but now I'm not sure if I can. Do I have to cover it with a metal / poly-carbonate or laminate / rubber material?

I also read some posts where people have said that if they were to do things differently, they would put the posts in cement posts. Not sure how I would do that with the frames method.

What I thought would be a simple project has started to become a mammoth task to figure out, lol.

Anyway, my mind is drawing a blank now - been at this too long so I'll stop here. I tried to make a mock up of my design idea in sketchup so will try to attach the pic to this post. it's not accurate, just something to help me figure what I'm doing.




Really appreciate your assistance on this.

My main ideas from (and credit to):
1. http://www.simplesuburbanliving.com/2016/03/how-to-build-simple-suburban-chicken.html
2. https://www.backyardchickens.com/a/the-triple-c-the-crouches-chicken-coop
3. https://www.backyardchickens.com/a/wichita-cabin-coop

Thanks again,

MK.

Hi MK, I'm in the process of building my coop now, and the design is very similar to yours. For the roofing, I think you'll find better options than plywood that are likely somewhat less expensive and better suited. I spent hours researching roofing, and decided going with Ondura roofing panels they sell at Home Depot or Lowes. They are fiberglass/asphalt corrugated panels and are about $20 each here for a 6x4 panel. I'm also putting plywood over the coop for insulation, but just roofing over the run.

For joists, I was planning on 24" oc but may go down to 16" as I only have a 1' drop front to rear (8' to 7'). The spacing you choose really depends on a number of those factors: how much snow you get, roofing material, pitch, etc. I would use 2x4 at a minimum of 24", and reduce to 16 if you get a lot of snow.

Best of luck!

Mike

I have no idea how much snow, ice, or wind load you may get. If you look through your local building codes you will probably get some information. Your librarian can probably help you with that and you should not have to buy the codes if you go to the library. They may give you pound per square foot loads which may not help you much but some places give sizes and spacing.

Wind load can be significant. I had a shed roof similar to what you are showing come off and fly a few hundred feet in a straight line 70 mph wind. I didn’t build it, it was here when I moved here but they used fairly short smooth nails to attach it. I used long ribbed nails when I replaced it.

Stick with either 16” or 24” spacing. Most of your construction material comes in 4’ or 8’ dimensions. It just works out better when you use those because they add up to 4 feet.

Two feet height difference from front to back over 8 feet should allow you to use about any roofing material you want to. A flatter roof won’t drain well so water pools and either rots or rusts it or leaks through. If I have your dimensions down right, the actual length of your roof will be over 9-1/2 feet. Plywood sheets aren’t that long so you will have seams in it that will leak. There are plenty of different roofing materials that you can use, shingles, metal, or plastic roofing, but because of the length plywood is probably not a good choice.

There are all kinds of different ways to build a foundation. What you want is something that won’t settle or allow the building to blow over. Concreting posts in is certainly one way, but pouring a concrete foundation, leveling heavy beams like 4x6 treated timbers, using cinder blocks, or many others can work fine. Some of it depends on how level your ground is and what kind of soils you have. Just make sure your building is anchored to the foundation so it won’t blow over.

Hi MK,

I'm also just finishing my coop like yours and my head was swimming after researching to make sure it was properly built. My foundation is 4x4's layed out, on cement cap blocks place below the ground level and a 2x4 sill plate, I wanted to make sure it could be moved if I ever wanted too. Otherwise I would have set 4x6 corner posts in footings. Since I was up in the air about what roofing I wanted when I began construction, I decided on a roof pitch 2/10, rafters were placed 24" on center with a modified double 2x6 header and stacked 2x4s for my studs/posts sideways spaced 4 foot apart. I've seen pole barn rafter construction spaced further apart with metal roofing with the use of purlins, but I really didn't research it.

Two web sites that were very helpful in planning the roof.

This first site, you enter your roof span, snow load and type of wood your considering and it will tell you what the American wood counsel recommends. With my roof, SPF rafters and a snow load of 5 (Georgia), it recommended 2x6 construction with the rafters being 24" on center. I want to say this information is only good for > 3/10 pitched roofs
http://www.awc.org/codes-standards/calculators-software/spancalc

This site, depending on your roof will tell you the layout and the exact dimensions for your birds-mouth and end cuts. Tip, you need to subtract your fascia board, if used, and roofing to get your 12" overhang if you want it exactly 12". Make sure you are on the imperial tab, otherwise it will give you metric.
http://www.blocklayer.com/roof/skillioneng.aspx

I went with a metal roof and 2x4 purlins, 24" on center with no plywood deck. It really depends what you would like to use for your roofing material and that roofing material recommended construction. I found a place locally that sells metal roofing which was cheaper than the big box stores. I considered shingles and condura too, but the metal was far easier to install and cheaper.

Feel free to ask any questions, however I'm not a structural engineer

Good Luck

Bill

We had that coop and didn't sink any posts, and we no longer have that coop... We had a bad storm with 70 mph winds that grabbed the roof and flipped the whole building over the fence. Amazingly, it survived that, but sadly did not survive being flipped *back* over. My husband was heartbroken. So if you get any severe weather like that, you might want to consider it. On a side note, all the girls were fine and are actually really thriving in their new free range life while I build a new coop

All the local chicken people I've spoken to so far are telling me not to worry so much about securing the coop to the ground or the foundation and that the style of roof doesn't matter, but I try to look up things like local wind maps and find that in NJ they can exceed 100mph! Now I haven't experienced that sort myself in the time I've been here, but there are some days, albeit rare, that it gets pretty **** windy and I really dont want to take the risk.

I'm thinking of sinking the corner posts in at least 12"-18" into the ground at the very least. Will this be enough or should I pour concrete down there too?

BBailey said:

My foundation is 4x4's layed out, on cement cap blocks place below the ground level and a 2x4 sill plate, I wanted to make sure it could be moved if I ever wanted too. Otherwise I would have set 4x6 corner posts in footings.

Click to expand...

This is exactly what confuses me - the posts just sit on the sill plate but isn't attached to it? Would really help if you have some pics to explain exactly what that means also. I'm guessing the cement cap block is just a slab and the sill plate is a flat frame lying on top to ensure the foundation is level all the way round and the coop frame just stands on this.

I don’t cement posts in but I grew up tamping rocks around them to hold them. If it’s done right that’s as good as cementing them. How deep they need to go depends a lot on your soils type: rocky, clay, or loose sand. How much wind area you have exposed makes a difference too. Without knowing anything about that for you, I’d suggest 18” should be enough if you cement them in.

I set my 4’ x 8’ grow-out coop up on posts. I cut the top of the posts off level and nailed 2x4’s to make a level surface, then put my grow-out coop up there. Then I used plywood plates to attach the coop to those 2x4’s. It’s tied together pretty well.

However you do it, anchors set or grouted in concrete, cinder blocks, or brick or by nailing or screwing wood together, I strongly suggest you tie the coop to the foundation.

A lot of structures are secured via gravity. I've made two different coops where the sheathing extends an inch or so past the bottom "sill". A platform on stilts is made 1/4-3/8 inch shorter in each dimension so the sheathing laps over it and holds coop on. New Jersey gets 100 mile winds if you live on the coast. regardless, for insurance just have a few anchor bolts you can take the nut off if you ever want to move it. Or for that matter just use screws. If your using posts the two reasons for wanting cement footings is if the ground can't support the weight in a small post so need larger area of footing or if you fear the post will rot over time being in contact with earth. In short, there is no need to cement a post for a chicken coop. Use pressure treated post and sink them in ground 16 inches. Coops are light and a 4x4 pressure treated post will last more than a decade sunk in the ground. It would take an enormous coop to warrant more surface area and friction contact than a 4x4 post 16 inches deep.

For what it's worth I'm also in NJ (Burlington County) and I'm not intending to secure mine to the footings. I have cinder blocks buried about 4" then a 6x6 foundation of 2x6 sitting on them. It is elevated off the ground and I'll have a similar style roof, but once all the framing is done it will be VERY heavy. I'm more concerned my roof panels will be ripped off by wind then that the building itself would move. We do get some heavy winds, especially during storms, but I can't imagine that they would be enough to move the building, and frankly I'm not sure the roof will be secure enough that if the winds got bad enough it wouldn't wrip off before the structure budged.

I'm no engineer and this could also depend on your framing, but I would think you'd be OK.