Need help designing an irregular-shaped covered run

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K0k0shka

Free Ranging
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Jul 24, 2019
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Boston Area, MA
My Coop
My Coop
Now that my coop is almost done, I'm starting to plan out the run. I'm creating a separate thread for the run so it doesn't get lost in the coop build thread (which you can see here).

I've been designing and redesigning this since last summer. The space I have is an irregular shape, which makes this tricky. There are trees and bushes in the way, and a raised garden bed. I want to give the chickens the maximum area I can though, and an irregular run is the only way to do that.

This will probably be long and I'll have lots of questions, so bear with me, I need to think this through. I appreciate any feedback!

So, here are my latest plans (standard map orientation, so the top is north):
Screen Shot 2020-02-14 at 9.08.35 PM.png


The run needs to go around the little tree that's next to the coop. That's a linden tree so it will get big, and I want to leave it enough room (it's very young right now). The whole area will have a sloped roof, sloping south to north, so towards the property line. The 3'x5' section of the run that's attached to the coop will have a lower roof - about 5' tall, just enough for me to walk under - to leave room for the linden tree's branches. The main section, the 11'x11', will be taller, sloping down from 8' in the front to about 5.5' in the back. I'm treating the 3'x5' and the 11'x11' sections as two structures with two separate roofs, just to get two regular shapes that are easier to work with, and then I'll have to connect them somehow (more drawings and questions on that later).

The original soil on our property was heavily contaminated with lead, so we had everything covered with several inches of clean fill after we moved in. So the surface is fine, but I don't want to dig. Which means no footing holes for the run structure. I want to lay down landscape timbers along the whole perimeter and use them as the bottom of the run frame. So the vertical supports attach to the landscape timbers at the bottom. Would that work? Any advice, best practices or red flags?

The fencing material
will be wrought iron mesh panels, which I got for free from a former chicken owner neighbor. They are about 3'x4' and I have 28 of them, enough to cover the whole run (with some HC patching for the irregular-shaped areas). The mesh holes are 2"x2". A bit big, but that's what I have. The coop door will be closed at night, and our worst enemies here are large, so I hope that's enough. I'll also have a denser HC apron along the ground and going up a foot or two along the fence. The panels look like this:
IMG_4891.jpg


The walls: the iron panels will stack on top of each other, two tall, standing on their short sides for the taller south wall (so 8 feet tall total), and on their short sides for the north wall, so a little under 6 feet tall. They are solid and very heavy. If the horizontal top beam of the run frame is resting on the top edges of the iron panels, can I count on them for support and use 2x4's for both the vertical supports and the top horizontal supports of the run frame? Or will I still need 4x4's? Or a combination of the two? How far apart should the vertical supports be?

The roof
will be partially covered year-round, with clear polycarbonate panels, so the chickens always have a dry outside area. The rest will have a welded wire mesh on top for protection (probably 2"x4" for cost purposes). I will only cover that part with polycarbonate in the winter, to keep the snow out of the run. The reason for that is because I have trees and shrubs either inside or immediately next to the run, and don't want to cut off their water supply during the growing season. I also want some rain water to get in there for the sake of composting the organic matter on the floor somewhat. The clear panels will allow light to still go through. The tree marked "HUGE TREE" on the right is a giant maple that shades everything, so I don't need additional shade, but rather, more light. As for snow load, I don't really know what to plan for anymore. This used to be snow country, but snow is actually rare nowadays. Every few years we'll get a giant snowstorm with deep snow, but most years there's barely enough for a snowman.

Now, questions about the roof:
▪ Will 2x6's be enough for the roof rafters? Will the fact that the roof will be resting on the iron panels all the way along the south and the north wall help distribute the load?
▪ If the rafters are 11+ feet long, will I need additional vertical supports somewhere in the middle of the run? Or will the rafters be enough?
▪ How far apart should the rafters be?
▪ The polycarbonate panels are only 2' wide, so I assume I'll need purlins as well, unless the rafters are 2' apart (which seems excessive to me...but maybe not?) What size wood do I need for the purlins? Will wall studs be enough? (1x2 or 1x3)
▪ How much of the roof can I get away with covering permanently without killing the bush inside the run and negatively affecting the linden tree? (the bush is a forsythia, so it's hardy, and rainwater will run off the roof and down directly behind the bush and hopefully water it, but still).

Thank you to whoever survived until the end of this giant post, and thank you for any feedback!
🐔🌿🌳
 
First thoughts are that an 11' span holding up a snow load like you can get in MA might not be properly supported by the wall structure you propose to use.
@DobieLover might have more detailed advice.

The original soil on our property was heavily contaminated with lead, so we had everything covered with several inches of clean fill after we moved in. So the surface is fine, but I don't want to dig.
This is concerning too......literally 'several inches' like 3"?
Chickens can dig down a good 6-8" or more.

Oh, and....any way at all to get rid of the angled wall?
Would make roof much easier to build.
 
Thanks for the reply, @aart !

First thoughts are that an 11' span holding up a snow load like you can get in MA might not be properly supported by the wall structure you propose to use.
@DobieLover might have more detailed advice.
I thought I might need supports inside the run. Any advice on how many, how far apart, etc?


This is concerning too......literally 'several inches' like 3"?
Chickens can dig down a good 6-8" or more.
We asked for 6” coverage but the bobcat wasn’t completely precise, so some areas got more, and others got less. Not sure about that particular area. I’m gonna dump a lot of wood chips in the run and monitor for excessive digging. And yeah, the lab results were quite concerning. Nevermind chickens, I also have kids in that yard :( But that’s just how urban areas are.

Oh, and....any way at all to get rid of the angled wall?
Would make roof much easier to build.
Not sure I follow... Which angled wall?
 
Red flag for no footer in freeze/thaw cycle heaving of your timbers.
There is no way that building a structure that large with just fence panels stacked together will support a roof. You will have to build a fully free standing structure and attach the panels to the structure. If you build without footers, expect movement. If you have no choice and are willing to risk it, I would lay down the timbers LEVEL, tie them together with heavy duty strapping and angle braces then screw down post anchors where you put your support posts that will hold up your beams. Yes, this is a lot of lumber and there is going to the associated cost.
You can easily support polycarbonate roof panels with the 4.4/12 pitch roof you are proposing. It will handle the snow load. I had 3' of snow dumped on polycarbonate panels with a lower pitch than what you propose and it held up fine.

I would use 14' 2x6 lumber for rafters and overhang the front and rear edges with the excess. Very much like I built here. Take a look at My Coop link for how this run was constructed.
run framing.jpg


You can do 2' on center for the rafters. I would use 1x3 for the purlins and they can be spaced every 2' or whatever the manufacturer of the panels recommends.
You will not want to only install the panels in the winter. Once they're up, they're up. Don't worry too much about one shrub in the run not getting enough water. It will adapt or die. Remember, the chickens are going to dig like diamond miners around that shrub and challenge it's survival more than any lack of water. It will still get water by sending roots out a little further and deeper.

I also recommend loosing the angled wall. If you do this, you will have a 12' length on the front side which is better for lumber purchases and you only lose about 13-14 sq ft of area.
run mods.jpg
 
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Thank you @DobieLover for your reply! I just read your coop page. Wow, how have I not seen this until now! It's amazing. So detailed and well written, fun to read, and what a professional job you've done. Your setup is beautiful! I really enjoyed reading about Fabio and the babies, too.

I had a feeling I might end up needing to dig holes. I was really hoping to avoid it, but I don't want the structure to collapse... And not just because of the lead, though that's reason #1. Another reason is because our soil is extremely rocky. I dug some holes to plant trees a few years ago (I know, the lead... but I wanted trees damnit, haha), and about half the volume I dug out was rocks. Major pain in the butt and so exhausting! I'm very intrigued by idea of post anchors though. I did not know they existed. If I used this kind:
post_anchor.jpg
instead of digging and pouring concrete, would that be enough? Will the rocky soil be a problem? I can rent a jackhammer so I don't bust myself hammering them in by hand.

There is no way that building a structure that large with just fence panels stacked together will support a roof. You will have to build a fully free standing structure and attach the panels to the structure.
No no no, I never intended to build the structure out of the panels alone! There will definitely be a free-standing wooden structure and they'll be attached to it. I was just wondering, since they will offer *some* support (unlike HC), will that give me leeway to maybe space the vertical supports farther, or use 2x4 instead of 4x4, or something like that. Basically, do I earn anything in terms of support because I'm using these panels and not floppy HC...

I also recommend loosing the angled wall. If you do this, you will have a 12' length on the front side which is better for lumber purchases and you only lose about 13-14 sq ft of area.
Ah, now I see what you both meant by the angled wall. Yes, that would make things easier indeed. I was just going for "more is better" and trying to eek out every square foot I could for the chickens :D But I guess the run will already be big enough, so I'll get rid of the angled section.

Don't worry too much about one shrub in the run not getting enough water. It will adapt or die. Remember, the chickens are going to dig like diamond miners around that shrub and challenge it's survival more than any lack of water.
I really don't want it to die though :( It would make a great hiding spot for the chickens, especially on hot days. It's nice and shady under it. And it's probably the only piece of vegetation I have that might survive coexisting with the chickens. I can put down rocks or pavers near the base if they start digging there, or put down HC, to protect its roots. And also, if I get rid of the angled wall, the roof won't extend so far out in front of the bush and it will still get rainwater pretty close by in the front, so hopefully that will help.


Thank you both for your comments! This is really helpful and I'm already reworking the design. I will get rid of the angled wall and cover the whole run permanently (hoping the bush lives). Do let me know what you think about using post anchors instead of concrete footers. And how far apart my vertical supports will need to be.
 
Thank you @DobieLover for your reply! I just read your coop page. Wow, how have I not seen this until now! It's amazing. So detailed and well written, fun to read, and what a professional job you've done. Your setup is beautiful! I really enjoyed reading about Fabio and the babies, too.

I had a feeling I might end up needing to dig holes. I was really hoping to avoid it, but I don't want the structure to collapse... And not just because of the lead, though that's reason #1. Another reason is because our soil is extremely rocky. I dug some holes to plant trees a few years ago (I know, the lead... but I wanted trees damnit, haha), and about half the volume I dug out was rocks. Major pain in the butt and so exhausting! I'm very intrigued by idea of post anchors though. I did not know they existed. If I used this kind:
View attachment 2027354
instead of digging and pouring concrete, would that be enough? Will the rocky soil be a problem? I can rent a jackhammer so I don't bust myself hammering them in by hand.


No no no, I never intended to build the structure out of the panels alone! There will definitely be a free-standing wooden structure and they'll be attached to it. I was just wondering, since they will offer *some* support (unlike HC), will that give me leeway to maybe space the vertical supports farther, or use 2x4 instead of 4x4, or something like that. Basically, do I earn anything in terms of support because I'm using these panels and not floppy HC...


Ah, now I see what you both meant by the angled wall. Yes, that would make things easier indeed. I was just going for "more is better" and trying to eek out every square foot I could for the chickens :D But I guess the run will already be big enough, so I'll get rid of the angled section.


I really don't want it to die though :( It would make a great hiding spot for the chickens, especially on hot days. It's nice and shady under it. And it's probably the only piece of vegetation I have that might survive coexisting with the chickens. I can put down rocks or pavers near the base if they start digging there, or put down HC, to protect its roots. And also, if I get rid of the angled wall, the roof won't extend so far out in front of the bush and it will still get rainwater pretty close by in the front, so hopefully that will help.


Thank you both for your comments! This is really helpful and I'm already reworking the design. I will get rid of the angled wall and cover the whole run permanently (hoping the bush lives). Do let me know what you think about using post anchors instead of concrete footers. And how far apart my vertical supports will need to be.
Those anchors will drive the load to a point and actually cause the post to sink.
If you read my coop article, I was thinking more along the lines of attaching the post bases that I used directly to the level timbers using long structural screws. Obviously footers are far superior. The footers took the longest time for me to make because my soil structure is the same as yours. Lousy with rocks!
For your design, you would need three posts for both the north and south walls of the large run section and two posts for the north and south walls of the small section.
I'd nail two, twelve foot 2x6s together to form each beam to sit ON TOP of the posts for the large section and again double 2x6s at 10 ft for the smaller section. Birds mouth the 2x6 rafters and attach them 2 ft on center, nail in the purlins and off you go. Don't forget the lateral cross-bracing running north/south and east/west to prevent racking.
 
Yes, got it about attaching the posts directly to the timbers, just wasn’t sure if post anchors would be better than the horizontal timbers. Seems like each has its own issues... But the timbers are a little less bad than the post anchors? I’ll probably end up needing to dig anyway 😭 If I do, how many posts do you think I’d need for the east/west walls of the larger run? Just the end posts they share with the north/south walls, or a third one in the middle as well? Also, would I need an additional post inside the run halfway down the rafter length, or will the rafters hold up on their own?
 
@DobieLover one more question for you, since you have wood chips and a covered run (aart's run isn't covered so her situation is different). How does poop decomposition work out in the run if it's kept dry? From what I understand, the idea is to mix the wood chips, poop, grass clippings and other yard scraps and, with the rain water and the birds turning it over, it composts and there's no smell. But what happens when you remove water from the equation? Or will I need to water it?
 
And another question. If I were to dig footings, how deep should they be? The 43 inches in @DobieLover ’s build article killed me :eek: Does it have to be that deep? That’s enough for me to stand in the hole neck-deep!!! I don’t think I can survive digging multiple holes like that:hit
 
And another question. If I were to dig footings, how deep should they be? The 43 inches in @DobieLover ’s build article killed me :eek: Does it have to be that deep? That’s enough for me to stand in the hole neck-deep!!! I don’t think I can survive digging multiple holes like that:hit
That's code depth in my area. You'd have to ask what the code depth is in your area.
When you install the footer you want it flared at the base to resist frost heave.
 

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