pole barn questions

[EddieWalker]

I see where some of the companies that specialize in pole barns are going to laminating boards together for their posts. In the few cases where I've seen this, they are attached to a concrete slab. From what I understand, 2x material is not rated for ground contact. It has less chemicals in it then the 4x and larger wood. If you are setting posts in the ground, with or without concrete, I would use wood that is rated for this application.

With youe posts on 8ft centers, be sure to use 2x6's for your purlins. I'd also make sure they were 16ft long and overloap the ends. If you are using metal siding, then every 6 ft would work, but if you are using OSB or plywood for your siding, you need to be have at least 4 ft centers on your purlins, and less if you are installling Hardi Lap Siding over the sheething. If you are thinking of a rock vineer, then 2 ft centers and 3/4 plywood is required.

While I can't speak for areas that get snow, here in the South, 7/16 OSB for roof sheething on 2ft rafters is code and very common. I've seen roofs where you can see the rafters through the shingles, but think that is from other causes. In one case, I saw this on a roof that was shingled when the decking was wet from a rain, and 15 pound paper was used with 3 tab shingles on top. In my opinion, they did everything wrong, and as a result, the roof looks like it. 3/4 plywood on a roof is allot of weight, but it's also allot of money that won't accomplish anything. For those that want to upgrade from OSB, 1/2 inch plywood is just twice as much money as OSB. 3/4 plywood would be about 3 times as much money as OSB. Whatever you use, don't forget the H clips.

Do you know how to build trusses? or will you buy them? From what you've written, it sounds like you are planning on building them. There are some websites that show how to build them. I'd do a search for this and copy the desing for your span and eve design.

While pole barns are very simple to build, what you use is based on what your eventual plan for the building is. If you are thinking of making it into a house one day, then it's important to plan for that now.

Good luck,
Eddie

 

[MarkV]

To me, given that you are not in an area that requires deep footings, I would pour a footing and stick frame. With a pole building that you plan to finish inside and out you add so much wood to support sheathing, siding, sheetrock, windows, ect. that you don't save much with a pole frame. Also I would price out trusses. You may well find them less expensive than roof rafters and ceiling joist type of framing. It would also let you expand the width of the building for a minimal cost which would lend itself to a house structure much better than 16' will. As far as rafter/truss spacing either 16" oc or 24" oc will work depending on the sheathing used. Here if you sheath with 3/4" then 2' on center is fine. If you use 1/2" then 16" on center is required.

MarkV

 

[aj1]

i dont really know how to build trusses i was going to put a 2x4 from the ridge board to the ceiling joist. cant buy prefab trusses i dont have a tractor to pic them up with. im going to use 4x4 post becuase if i get them any bigger i wont be able to handle them. i dont have money for footings or a tractor to dig them with. i will put some X braceing in the walls and maybe ceiling too for the wind. im going to set the post stick frame the roof stick frame the walls and floor. i cant count how many mobile homes 16'x80' i have seen with a pole roof over them using 4x4 post and 2x6 joist with 2x4 raffters 16" o/c. i know that will hold i just havnt seen that many framed out with siding and sheet rock and a wood floor should be just like a stick frame house just a bit taller most homes are 8 foot tall on 3 or 4 cmu blocks and 12 feet at the ridge middle

 

[GPintheMitten]

From your first post, you said 12 foot high, and I assumed you meant 12' at the eaves, but from your last post, maybe you are talking more like 8' at the eaves and 12' at the ridge.

These are major differences as far a wind load. It still sounds to me that you would benefit by looking at some plans or at least sketching some plans and posting them here to get some advice. I have no doubt that once you settle on a good plan, that you will be able to construct it, given your work experience. It just seems that the most help you need is on a good strong design that won't break the bank.

Plans don't have to cost a lot. You could probably find something workable on the internet for free or as mentioned earlier, some ideas from a lumber yard.

 

[aj1]

its going to be 12 foot at the eaves and 15 foot at the rige. no snow so i dont have to make a steap pitch. i will try to sketch something out later. i already got some good info and ideas from you guys. i dont have a tractor yet but i think im going to stick around on this site.

 

[Steve C]

i dont really know how to build trusses i was going to put a 2x4 from the ridge board to the ceiling joist. cant buy prefab trusses i dont have a tractor to pic them up with. im going to use 4x4 post becuase if i get them any bigger i wont be able to handle them. i dont have money for footings or a tractor to dig them with. i will put some X braceing in the walls and maybe ceiling too for the wind. im going to set the post stick frame the roof stick frame the walls and floor. i cant count how many mobile homes 16'x80' i have seen with a pole roof over them using 4x4 post and 2x6 joist with 2x4 raffters 16" o/c. i know that will hold i just havnt seen that many framed out with siding and sheet rock and a wood floor should be just like a stick frame house just a bit taller most homes are 8 foot tall on 3 or 4 cmu blocks and 12 feet at the ridge middle

Even if you used pre built trusses with a span of only 16 foot they would be light enough for you to install yourself without anything more than a good ladder.

I think the 2x4's will work fine for rafters. I have a house here in Northern Michigan that was built in the late 20's. It is 28 foot wide x 38 foot long and it has 2 x 4 rafters on 16" centers. The 2x4 's they used were not long enough so they spliced them end to end with scab plates on the sides. It isn't pretty to look at but it is still standing 80 years later. I have done some extensive remodeling and have reinforced the roof, but even after carrying a northern Michigan snow load for 80 years it had only sagged about 5 inches at mid span in the center of the house. My roof has about a 9-12 pitch so that may have helped. In your climate I would use a 4-12. I have also removed some load bearing walls so I installed a 20" built up beam to carry the weight of the ceiling in the living/dining area. I also jacked up the roof and removed all the sag out of it.

 

[towmotor]

If your trusses are only 16 feet long, then you should be able to make simple king-post trusses, using only 2x4's, and don't bother with a ridge board.

You could have engineered trusses made, and if you're planning to use your building as a dwelling later on, you really should go that route, just so you can avoid trouble with building inspectors.

As far as lifting trusses into position?; You should be able to lift a sixteen footer with one hand.
I installed 20 footers with one other guy on my two story (gambrel) house, so you should be able to do it with no sweat at all.

 

[aj1]

what do kings trusses look like? that may save me money if i dont have to use 2x6 joist i wont need ceiling joist right? the truss will be the joist and the rafters. you guys are right 4x4 post are too small.

 

[dave1949]

what do kings trusses look like? that may save me money if i dont have to use 2x6 joist i wont need ceiling joist right? the truss will be the joist and the rafters. you guys are right 4x4 post are too small.

Check here. About 1/2 way down the 1st page.
en.wikipedia.org/wiki/King_post

The truss takes care of the ridge board, ceiling joists and rafters.

Usually trusses can be ordered at any lumber yard and delivered to your site on their truck.

Dave.

 

[Scotty370]

If your just looking for ideas: Roof - Google Images