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Hi ya’ll – I’ve been away for a while (building MY shop and finishing MY house), but now need your learned opinions on pole barns – my first is happening soon.
I’m going to build an 80′ X 100′ pole barn, 40′ clear span along the center with flanking 20′ bays; all to hold construction and landscaping equipment. I’ve got teplephone poles and a mill to cut (my) timber for trusses. The rule here in GA is that you can build pole barns with your own green lumber.
I have been through the FH archive, and have a 16 page word document with the knowledge of the ages (at least since 1998).
Given all that, does anyone have further pearls of wisdom to drop on me about trusses or roof form? Is there any advantage to having a truss over a taller central bay (40′) with lower sheds abutting both sides? Is that easier to build than a continuous truss? How the heck would one handle an 80′ truss anyway?
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No pearls here, but handling an 80' truss? Hire a crane firm and have 4 - 6 knowledgeable carpenters upstairs to handle it being lowered and nail it in place. One person per end, one at the top and space your others in between, depending upon experience, have another smart person on the ground to help guide it. Hope this helps, good luck.
*Bill, I'm sorry but the use of cranes in this application is yesterdays technology. It requires to many people and is too slow and expensive. Briefly you erect pole buildings with a rough terrain telescopic forklift. You don't need 4-6 carpenters. The forklift operator picks up the bundle of trusses, (so you don't need someone on the ground to strap the load for the operator sitting in the cab.) then you raise the load up and drive into the building. when you get to where the first truss goes you set it doen on the top plates (one carpenter on each end) and back up to your next location, where you drop the next truss. continue untill all of the trusses are up. then you put your work basket on and use that as your stageing to fasten the trusses to the top plate and carefully space eac truss the right distance. Then you grab a bundle of plywood and extend the boom as you drop off the plywood. (that way you're sliding plywood and dropping rather than lifting plywood) Use the forklift to lift the shingles up to the roof and set the work platform under the workers as fall protection and a flat place to set tools and take a break. Putting the skin on is a lot easier with a forklift because when you're done with a section you just move the forklift. no up and down ladders, no heavy lifting, no shaky scafolding to erect and move. Average rental price for forklifts is about$600. a week or $1800 a month (that get's you a new or near new Lull, Gehl, or Ingersol Rand 6000# forklift with 40+ ft. of boom. figure about $75 a week or $200 a month for a 16ft.x4ft. work platform. Since you can build it effeciently with a crew of three instead of 6 it's a lot cheaper than the labor and if you do this for a living rent it for about 5 years and it's paid for. (the useful life of one of these is about 20 years plus when used by a carpentry crew) The great thing is evan with a crew of only three you will be finished about 20% faster than without the forklift.
*Frenchy, Thanks for the update, in the rural upstate NY area where I live, I guess we do it differently. Forrest is building a smaller pole barn than what I am used to, ie-200-300 dairy cows. In any event, I'd allow for light and some power in case your're in their at all hours and need a coffee maker next to your sawzall. Be careful positioning those poles, they're heavy. Good luck.
*Hi Forrestyour barn is more ambitious in scale the pole barn the I just finished (36'x36'). However let me tell you about a problem I encountered in pole construction. It's very hard to set poles plumb with any accuracy. They're very heavy, awkward to manipulate, and I found errors of several inches at the top of my 20' poles.I'm not sure how to set big poles with more precision (any ideas anyone?) but it needs to be done better than I did, in order not to run into problems during roofing and siding.good luckLes
*Basically Les, when working with round poles, I just try to find the straightest face by sighting down it, put it to the outside of the building and hang a plumb from the height of the eaves with a piece of 2x scrap.Forrest, one of the advantages of having the central structure taller than the tipouts is that you can install light panels up there or leave it open under the eaves for ventilation. Also, if you have enough poles and dont have your heart set on a clear span in those 20' tipouts, you could run an extra line of poles down the center of one or both and just use 2x6 rafters instead of trusses.JonC
*Les, Yes, use a rough terrain telescopic forklift to set poles. (see above post) with one of those it's sooooo easy to set them plumb. Again, you have to use the right tool for the right job. Lacking that tie three ropes to the pole and have three helpers equally spaced tug until they are vertical. Use the right equipment or get enough people. But forklifts don't ever show up drunk, late, or not at all . they never have babysitting issues or argue with the boss. No one has ever had to file a workmans comp claim on a forklift. (nor been taken to court by one)
*You may want to pick up some books. "Low-cost Pole Building Construction", by Merrilees, is an update of "Pole Building Construction" by the same author, now out of print. That book was kind of a hippie-DIYers-on-the-commune-get-together-and-build-their-very-own-barn-themselves! book, but talks about using round poles, etc., and may prove useful to you considering it sounds like you're about to embark on a similar endeavor. Round poles are tapered and can be tricky. "Practical Pole-Building Construction" by Seddon is rumoured to be useful as well, but I haven't read it. On pole barns around here (NW Oregon), most guys use factory-built trusses especially designed for pole barns. They're made from stress-rated 2x lumber, I believe. Assembling your own trusses from green ungraded lumber? 'might get interesting.Anyway, the trusses are used in pairs around here, one on each side of the poles. The poles are usually rough-sawn rectangular western hemlock, CCA treated to 0.6 psf (i.e., very green in color). Poles are set 12' O.C., and the roofing it held up with 2x6 purlins installed 2' o.c. Wall supports are also 2x6's, again spaced 2' o.c.Les, You don't need to worry being a couple of inches out of plumb at the top of a 20' pole. The important thing is to get the spacing at ground level accurate (within 1/4 inch), and the poles reasonably plumb (I've found this easier to manage if a put a level concrete pad at the bottom of each hole). One the poles are anchored you can tweak the position of the tops with come-alongs, braces, etc., until the wall and roof framing is installed. Also, at least with the square posts, it's a good idea to get the walls and roof up reasonably fast, as once the sun starts hitting the poles some of them are bound to start to bend and/or twist. Once the framing is installed, they're restricted from doing this too much. If it's too late and the pole has really twisted alot, it's usually better to leave it and attach the framing with blocking and shimming, rather than cutting the pole short and attaching another piece -- the walls get most of their racking resistance from the bending resistance of the poles themselves.I've usually seen the trusses raised in sets of four. First, the trusses are stood up at ground level, against their respective poles, on two set of adjacent poles. Then, the purlins are installed, usually with joist hangers, connecting the two pairs of trusses. This then forms a fairly stable unit, which is winched up into place with 4 manual winches, one at each pole.
*Forrest, I never did a big pole barn but my little sister finished one last year (actually a riding arena) with 80 foot trusses. She says they weighed 1200 lbs each and she rented a crane to put them up. If she can do it, so can you. She also had 3 or 4 helpers.
*80 ft. clear span trusses are not to be toyed with!If you go that route you need someone on site who has experience with setting them. you will need a crane it will take two lifting points 20 ft. apart a forklift will not work, do not even try that,you'll end up with 400 dollars worth of scrap for each truss you try to pick up. I have set 80 ft. trusses I fear / respect them it is not for the inexperienced.
*atoz, Commercial pole builders do it all the time here with telescopic forklifts. I don't know exactly what the widest I've seen handled but it's at least 80 ft. if not wider. Of course you need to use a strong back to pick up those wide trusses. If you don't, it won't matter if it's a crane or a forklift. Yes, some dummies will try to handle them with one rope wrapped around the peak and turn them into junk. I've seen that happen to crane operators as well as forklift operators. (by the way I sell cranes as well as forklifts, so I have no real ax to grind. If you want to use the much more expensive crane and pay for the extra labor I'll be glad to sell a $250,000 crane over a $70,000 forklift Or rent you either one)
*Thanks guys for all your help - I'll be going with a taller center bay (44') and lower wings (18') with corrugated vertical light panels at the clerestory. I've condensed all your responses and the archival stuff into a dense 12 page Word document that reads like a manual of what to do and what not to do.I feel much more confident now!Forrest
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Hi ya'll - I've been away for a while (building MY shop and finishing MY house), but now need your learned opinions on pole barns - my first is happening soon.
I'm going to build an 80' X 100' pole barn, 40' clear span along the center with flanking 20' bays; all to hold construction and landscaping equipment. I've got teplephone poles and a mill to cut (my) timber for trusses. The rule here in GA is that you can build pole barns with your own green lumber.
I have been through the FH archive, and have a 16 page word document with the knowledge of the ages (at least since 1998).
Given all that, does anyone have further pearls of wisdom to drop on me about trusses or roof form? Is there any advantage to having a truss over a taller central bay (40') with lower sheds abutting both sides? Is that easier to build than a continuous truss? How the heck would one handle an 80' truss anyway?