Questions about posts and SunTuf roofing

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by LindaN, Jul 26, 2008.

  1. LindaN

    LindaN Chillin' With My Peeps

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    I need a run and I'd like it to be covered so it will stay more dry and protect the hens a bit more during inclement weather.

    The run will be built along an existing fence on two sides, so it should only need 2 sides constructed and a gate to get inside. It will be approximately 20 feet long by 5 feet wide. I want to use the SunTuf polycarbonate for roofing [which has to be special ordered at my local Lowes...no one seems to carry this stuff in stock in Chicago.]

    I'm not handy, nor do I have tools or much spare time so I went the route of getting some quotes on the work. That didn't work out for me at all. No one seems willing to do the work as needed, unless they can incredibly over-engineer it. [I had one person tell me the job would require sinking 20 posts, because the roof would need support!!]

    So, it looks like I will have to wing this one myself. I'll have to take a week off of work (and soon since I have 3-week old chicks in my basement right now) and try to do this myself with borrowed tools and some female ingenuity.

    I don't *think* that a polycarbonate roof will need to have a lot of support. Am I wrong? Couldn't I just secure it to the top brace of the existing 6-foot fence and the top brace of the to-be-constructed run wall? If I don't run trusses (or whatever the heck they're called) will the roofing not be secure enough?

    Also, do I *have to* dig post holes for the new run wall? If I use a heavy 4X4 along the bottom and secure the wall posts to it is that enough? If I take this approach will my structure fall down in the next strong wind? I've seen structures on this board that don't look like they are constructed with posts sunk into the ground, so I'm hoping I can use that approach.

    The only real drawback I can think of with this approach is that the "sill" could rot quickly being in contact with the ground. So, I would first lay out and level concrete paver bricks (I have lots left over from another project) on the ground and actually have the "sill" on that. I'd also use cedar, which is rot resistant.

    Advice will be greatly appreciated. I'm pretty scared to do this on my own, but it doesn't seem like there is any other option at this point.
     
  2. SundownWaterfowl

    SundownWaterfowl Overrun With Chickens

    I used that on my coop. It was easy to attach and it allows the sun to shine through.
     
  3. LindaN

    LindaN Chillin' With My Peeps

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    Sundown Waterfowl, how big is the run you're talking about? Nice to hear you like the material, but I'm trying to figure out some details about how the it must be installed so I know what I'm up against.
     
  4. patandchickens

    patandchickens Flock Mistress

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    Quote:Oh no, you need decent support under ANY roofing material, even plywood, even roof-gauge steel.

    As luck would have it I have the informational flier about Palruf and Suntuf from our local Home Depot that I put in my purse when I was there a few months ago (am debating using it myself).

    You absolutely totally definitely need rafters and nailers (purlins). The amount depends on the load the roof needs to support (generally in a not horribly windy area this comes down to the snow load you need to engineer for in your area. Where I am, IIRC it is 40 lbs/sq ft. Let's pretend that, living in Chicago, your snowfall is similar to ours -- if not, you could loosen up *a little* on these numbers) For a 40 lbs/sq ft snow load, the Suntuf pamphlet sez your nailers (the horizontal members - the ones that the roofing material is screwed into) should be on 2' centers (i.e. 2' apart, on center); the rafters supporting them, i.e. the slantingly-vertical members that hold up the nailers, should be 1-2' apart on center "depending on building code". (For a chicken coop I would unhesitatingly go with 2').

    The rafters, just to be clear, rest on beams (on along the top edge of the roof, one along the lower edge) that are held up by yer posts [​IMG]

    Being as your roof is not very wide (a 5' span would be, what, maybe 6' to 9' actual pieces of roofing, depending on the pitch and amount of overhang), some people might cheat a bit further on the rafter-spacing numbers. They affect how strong the whole roof is. However it would be real unwise to cheat on the nailer(purlin)-spacing numbers for your snow load rating, because THAT spacing is what determines whether the roofing itself will crumple or crack. Neither Suntuf nor Palruf is especially rigid, btw - it can be cut with a utility knife or tin snips.

    Can I strongly recommend that you find a good book or even just website that outlines basic shed-roof construction techniques. You really need to know the basics if you're winging it, to avoid wasting mucho time and money and potentially having things fail once chickens are in there. I have to go make dinner right this instant or there iwll be a mutiny, but I will look at the names of a coupla books on my shelf for you to post later on, and also there are various state extension service websites with good simple plans for this sort of thing. You might try googling 'pole building shed roof" and see what you find, or something like that??

    Also, do I *have to* dig post holes for the new run wall? If I use a heavy 4X4 along the bottom and secure the wall posts to it is that enough?

    There are two main hazards of doing it that way. First, as the ground heaves up and down, the structure will move up and down (almost certainly unevenly), which can twist and rack the joints til the structure begins to come apart. A whole lot of extra diagonal bracing (using lumber or stout plywood - wire mesh or plastic will not do it) can help a little but really if the ground goes up you are not going to be able to stop it. And secondly, it makes the whole enchilada vulnerable to being pried away from whatever building it is attached to - by storm gusts, by you stumbling against it the wrong way, by a very strong dog trying to get in, etc. So it is kind of one of those 'proceed at own risk' kinds of things.

    Good luck,

    Pat​
     
  5. hollybird

    hollybird Chillin' With My Peeps

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    you might try solexx. it is 4'1" wide and then you pay buy the foot. or get it in pannels like 8' or 12'. flat but flexible. easy to work with and cut.
     
  6. SundownWaterfowl

    SundownWaterfowl Overrun With Chickens

    Quote:Oh. Well my run is about 8' I think. It is a playhouse coop. The roof isnt flat, it is angled.
     
  7. LindaN

    LindaN Chillin' With My Peeps

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    Pat -- ah, how could I forget about factoring in snow load!!

    I think what I'm going to do now is go back to the one fencing company that gave me a decent estimate (but refused to put on the SunTuf) and work with them on some minor modifications for the construction of the run itself. They can do the difficult stuff: put the post holes in place, build the gate/door, and install the wire.

    It will be constructed uncovered, but I can go back and do the roofing later.

    What other options are there for covering the run to keep predators out in the meantime? I know some people have Top Flight netting over their runs, but I don't think that will keep out a racoon, will it?
     
  8. WoodlandWoman

    WoodlandWoman Overrun With Chickens

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    Why did they refuse to put on the SunTuf? Because it would be a roof and they don't do roofs? Can you get them to do framing for a wire covering? Just have them use the same specs that would be used for the SunTuf. Then you can add the SunTuf later if you want, to some or all of the run.
     
  9. LindaN

    LindaN Chillin' With My Peeps

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    Yes, the reason they didn't want to tackle the roof is because that's outside of their area of expertise. They said they don't have people qualified to do it.

    The one general contractor that I brought in for an estimate told me I'd need a total of 20 posts if I made the total size of the run 12 ft X 20 ft. Most of those posts were to support the roof, they said. I think that's really over-kill.

    The fencing company is talking about putting in a total of 4 new support posts for a 12 ft X 20 ft run (based on ripping out one section of existing fence to re-configure the placement of the gate, and one 20 foot side already existing). So that 20 post comment really confused me.

    I thought dropping the width of the thing to 5 feet would be better if I do it myself because then I don't have to rip out the existing fence on one side to move the gate. However, if I'm going to have to get a fence company out here to build the enclosure, I may as well have them do the thing right and re-do that fencing. Instead of making the run 12 feet wide, though, I think I'll adjust that down to 8 feet. That will make it easier to do roofing when I can around to it myself or have someone else do it.

    Frankly, I think I'm having such trouble getting someone to do this the way I've planned for two reasons: lack of experience with the materials (polycarbonate roofing just isn't done around here for some reason) and concern for liability. *sigh* I guess this is what happens in a sue-happy society!
     
  10. patandchickens

    patandchickens Flock Mistress

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    Quote:It depends on what size posts. If you used 6x6's, you would need 6 posts and the structure would be clearspan. (In fact this describes the east not-quite-half of my big horse shed [​IMG]). But if you want to use smaller lumber you will need significantly more posts. I can see where using 4x4's you might indeed legitimately need something like 20 posts for that size structure, especially if you have 2 doors (that adds 2 extra posts unless your structural post spacing is pretty close). My gut instinct would be that if you wanted the structure to remain clearspan, you would be looking at something like 18 posts. That is just a layman's guesstimate. There are engineering tables where you can look these things up, you know.

    The fencing company is talking about putting in a total of 4 new support posts for a 12 ft X 20 ft run (based on ripping out one section of existing fence to re-configure the placement of the gate, and one 20 foot side already existing). So that 20 post comment really confused me.

    Holding up a roof is VERY VERY DIFFERENT than just 'being a fence', though. You can't go by what they say is sufficient for a fence. And I would be cautious of accepting their possibly-seat-of-pants numbers for what would be needed for shed roof support, if that is not a thing they actually do. I found the relevant tables online six years ago when designing our horse shed - some assiduous googling should turn them up, or you could just look for online plans for a 12x20 shed-roofed pole-built shed (which is what this run will be -- once you start talking about putting a solid roof on it, it is a SHED, really).

    Good luck,

    Pat​
     

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