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Thread: Truss spacing for new pole "barn"

  1. #1
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    Truss spacing for new pole "barn"

    Has anyone built a pole/post building with 4' between trusses? I have always used 24" centers but I read that 4' or more spacing will work fine. I'm planning to start on another building soon, an equipment shed.

    This shed will be a 24'x72' to keep farm and dirt working equipment out of the weather. No permits or inspections needed.
    (I leveled, compacted, and graveled the site almost 10 years ago and ran water and power 1000 ft in a trench so the site is ready.)

    - 6x6 PT posts every 10', 36" in ground with concrete pad and collar
    - Double 2x10 or 2x12 beams
    - gravel floor, 10' or 11' to bottom of trusses
    - Metal roofing with 2x4 purlins laid flat on 2' centers, 3-in-12 slope
    - I usually use 4x8 sheets of OSB under the metal roofing but may skip that here
    - Metal siding with 2x4 girts on 2' centers
    - Manufactured trusses with 2x6 top chord, 2x4 everywhere else
    - Trusses on 4' centers unless I'm convinced otherwise

    Any words of wisdom?

    JKJ

  2. #2
    Not knowing how much snow you get it's difficult to make a suggestion. I'm near Dallas and the most snow we get is about 2". My shop is 30' wide and I space a heavier truss 14' apart and run 2x6's horizontally between trusses like purlins on a metal building.

  3. #3
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    Quote Originally Posted by Edward Dyas View Post
    Not knowing how much snow you get it's difficult to make a suggestion. I'm near Dallas and the most snow we get is about 2". My shop is 30' wide and I space a heavier truss 14' apart and run 2x6's horizontally between trusses like purlins on a metal building.
    We get almost no snow, maybe a couple of inches at a time which is gone in a day. About 40 years ago I saw 8" but that hasn't happened again!

    I'll check into using 2x6 purlins instead - that sounds like a good idea. I would love to space trusses at 10' so I can fasten the end of each one to the posts.

    When you say "heavier truss", just how heavy. Is it made with larger 2x lumber?

    JKJ

  4. #4
    Get your truss builder to design the trusses. Morton buildings uses trusses 4 feet on center with 2 X 4 flat ways to fasten roof sheets to. To space the trusses at 10' OC, you will need to use either 2 X 6's vertical, or metal purlins. The 2 X6's will need vertical blocking at both ends and in the middle. I assume because this is a "farm building" you won't need a permit.

  5. #5
    I suppose it's because I'm not a contributing member but I'm unable to post a picture. I found an illustration, it's figure 4. http://www.fao.org/3/c3848e05.htm. As best as I can describe it I run 2-2x6's for the top cord and the ceiling joist with the verticals between them. The joints on the ceiling joists are staggered from one side to the other.
    Last edited by Edward Dyas; 09-02-2019 at 11:18 PM.

  6. #6
    Join Date
    Feb 2013
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    Tippecanoe County, IN
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    My barn, built in 1986, has the trusses on 8' centers. Purlins are 2x4 on edge.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  7. #7
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    Quote Originally Posted by David L Morse View Post
    My barn, built in 1986, has the trusses on 8' centers. Purlins are 2x4 on edge.
    ...and in Tippecanoe County, we definitely get more than 2-4" at a time. We've had multiple 12-18" events in the last 25 years.
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


  8. #8
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    I live just south of Cleveland and mine has 8 foot on centers with 2x4 purlins on edge. I worked for a pole barn builder and did many 4 foot on center buildings. You just have to size the truss correctly

  9. #9
    6x6 posts on 12' centers. Support beams are double 2x8's let into the posts and thru bolted. 3' centers. 2x4 purlins on 4' centers. We built our barn 30 yrs ago. That's probably overbuilt but it has gone through 2 hurricanes .

    IMO there are other more efficient ways to build a barn, using 2x8 rafters on 8' centers with 2x6 purlins in between (flush with rafters with hangers). I considered doing it this way, but the material and labor costs are higher.

    You can also mount the purlines upright instead of flat, so you could increase the distance between the rafters.

    If I were building a barn today, I would do scissor trusses on 12' centers with 2x6's in between on hangars.

    Check RR Building on YouTube he shows a post and beam method that looks good to me.

  10. #10
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    John,
    If you haven't already checked out RR Buildings YouTube series, it's worth a look. Lots of pole barn type construction. This one does an 8' truss spacing.
    https://www.youtube.com/watch?v=40tD...6s4Cv3&index=3
    Last edited by Ted Calver; 09-03-2019 at 11:12 AM.

  11. #11
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    If your building department is like ours you're going to need an engineer's stamp on the drawings to get them approved. Have her tell you what you need.

  12. #12
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    Quote Originally Posted by roger wiegand View Post
    If your building department is like ours you're going to need an engineer's stamp on the drawings to get them approved.
    Fortunately, no permits or inspections are required here for buildings and such related to agriculture. The county kept control of is the setback so the only constraints I have are self imposed.

    My building will certainly be engineered properly. I was looking for experiences with truss spacing to help hone in on some options before I approach my personal architect and engineer (in the family) and stop by the truss company for the order.

    Thanks everyone for the comments. I like the idea of scissors trusses for the extra clearance. i considered using them in my shop but decided I wanted a flat ceiling.

    JKJ

  13. #13
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    If you do go 4 or 8 foot centers let the truss company know as they will build a truss for that

  14. #14
    we often get a heavy wet snow. When our pole barn was built, the plans called for 4 ft centers on the trusses. and 4x6 uprights every 8 feet. I had the builder put the uprights every 6 ft (to accomaodate 12 ft stalls and also put trusses every three feet. Cost a little bit more, but not as much as I expected. A couple years later, we had 16 inches of snow followed by a terrible rain and barns /wharehouse roofs were collapsing in the area. I was glad I had the thing over built.

  15. #15
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    Quote Originally Posted by roger wiegand View Post
    If your building department is like ours you're going to need an engineer's stamp on the drawings to get them approved. Have her tell you what you need.
    Roger, I'd like to say thank you, and congratulations! You used "your", and "you're" in the same sentence, and both correctly! Very rare these days for posters to get one right.

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