Truss spacing for new pole "barn"

[John K Jordan]

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

[Edward Dyas]

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.

[John K Jordan]

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

[Bruce Wrenn]

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.

[Edward Dyas]

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.

[David L Morse]

My barn, built in 1986, has the trusses on 8' centers. Purlins are 2x4 on edge.

[Jason Roehl]

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.

[Jerome Stanek]

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

[Robert Engel]

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.

[Ted Calver]

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=40tDSx1j65o&list=PLvo-lhQgsIOg7Yh3aaLwkUJviPv6s4Cv3&index=3

[roger wiegand]

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.

[John K Jordan]

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

[Jerome Stanek]

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

[Perry Hilbert Jr]

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.

[Tom M King]

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.

[James Waldron]

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.

The grammar police have spoken! We are all safe.

[roger wiegand]

There are people who don’t know that their grammar is so bad they’re hard to understand.
It’s not so hard to use each word in its correct place.

:D

[Todd Mason-Darnell]

To get to the OP's question,

I have built several pole barns. I generally do 24 OC spacing, but I am also a conservative builder. The only issue I see with the spacing is that with the 2x4 on flat with the 4 ft OC spacing is that they will sag and it will make it "interesting" if you have to get on the roof for any reason. At a minimum, I would recommend turning the 2 x 4 on end.

Just to make a general argument, if you switch to 24 OC for your trusses, you will have a building that will last for 50 years or more and added the costs are not significant.

[Jerome Stanek]

My pole barn has 8 foot centers and it is 30 years old and still looks new. We do get a lot of snow here also as I am in the snow belt.

[James Waldron]

There are people who don’t know that their grammar is so bad they’re hard to understand.
It’s not so hard to use each word in its correct place.

:D

If each word had to be used in it's "correct place," there could be no poetry.

(You have a point, but IMHO, you have made it poorly.) :D

[Ronald Blue]

I think some of the comments indicate no knowledge of pole buildings. Now on to the original question. I'm not saying Morton won't use 4' spacing but that would be based on the customer's insistence. Maybe in ultra high snow load areas. Here we get snow but nothing like northern Michigan or Wisconsin/Minnesota. My building has them 8' on center. We had 16" in one snow last winter with no issues. I went with perma column posts. That's precast concrete in the base and the truss sandwiched between laminated posts. Here's a link for them. You will notice the photos show probably 8' spacing's.
https://www.permacolumn.com/

[John K Jordan]

I think some of the comments indicate no knowledge of pole buildings. Now on to the original question. I'm not saying Morton won't use 4" spacing but that would be based on the customer's insistence. Maybe in ultra high snow load areas. Here we get snow but nothing like northern Michigan or Wisconsin/Minnesota. My building has them 8" on center. We had 16" in one snow last winter with no issues. I went with perma column posts. That's precast concrete in the base and the truss sandwiched between laminated posts. Here's a link for them. You will notice the photos show probably 8' spacing's.
https://www.permacolumn.com/

Those posts look interesting.

A friend who has built a lot of pole buildings and barns has talked me into checking out metal trusses. I've never used them before but he said they are lighter, stronger, quicker to put up, and provide a lot more height inside.

JKJ

[lowell holmes]

http://www.southernpine.com/span-tables/joists-rafters/

This site will help.