Pole Barn - Why not use center post?

[tulenutn2o]

Hi folks,

This is my first post. I have read for days and days about pole barns. Great info! Still have a few questions that "google" has not been able to help me with.

Looking to build a pole barn and trying to understand why everybody is using clear span- trusses?

The size I would like to build is 30x50. 5- 10' wide bays.

1. Why not use the center post method like in the picture below and eliminate all the roof trusses and extra lumber cost? Seems it would eliminate the need for a crane or FEL as I don't have either.

2. Is there any down sides to this design?

3. Right now home depot has 2x8 Yp lumber is cheaper than 2x6. Using 2x8x10 for the purlins seem like over kill? 2x10 for the rafters (?) (outside post to center post) ???

4. Thinking I will use 2x8 hangers for the purlins off the rafters - any downsides?

5. Wanting to make my post 3 or 4 2x6PT laminated. I understand the ground contact version is what should be used - but I am thinking if I coat the post with "fence asphalt paint" that it will add enough protection? The TSC has some called "black beauty".

FYI These pics are from polebarn101 website. They are not mine and I am not connected to them - just the only pics I could find like this.

Also I am in east GA and the barn will be used for keeping a pickup, tractor, implements, two trailers, lawm mower etc. No livestock etc. Thanks

Along with the other good reasons for not doing it that way is: Time is a huge factor. Trusses go up much faster than stick framing a roof.

 

[gabeancounter]

blueriver,

so you are going to use a ridge beam, rafters coming down to top plate, then purlins in between? Seems like about the same amount of wood as just running rafters on 24"oc?

 

[blueriver]

blueriver,

so you are going to use a ridge beam, rafters coming down to top plate, then purlins in between? Seems like about the same amount of wood as just running rafters on 24"oc?

No sir ... the poles are 10'OC and the rafters will be trusses 5' OC .. the purlins will lay on top of the rafters 2' OC

 

[gabeancounter]

Along with the other good reasons for not doing it that way is: Time is a huge factor. Trusses go up much faster than stick framing a roof.

I have only helped build one barn in my teens. So I am not sure about the speed of either method. The method that I am talking about is not the standard stick built roof. No ridge beam. Like the second pic above there is only rafters at each post. Then place the purlins.

I think the 12 boards could be set in the same time as trusses. Now am I really going to save any money using this method? Maybe not.

I need to read a little more about how to set trusses. Use hurricane straps? toe nail etc?

 

[blueriver]

I need to read a little more about how to set trusses. Use hurricane straps? toe nail etc?

The poles will extend beyond the top plate, nail the rafter directly to the pole setting on the double plate ... I will use a 40d ringshank nail ... try to pull them out. Use a chainsaw to cut the pole to the top angle of the rafter.

To set them I will put the tail up on one side and then raise the other end up, thus the rafter will be hanging upside down inside the barn setting on the outside double plates and then swing the top of the rafter up and hold in place while it is being nailed on both ends ... purlins will then be nailed across to hold them ... the first or end rafter must be well braced and tied off so not to loose the rafters as they each go up and into place.

 

[gabeancounter]

BR,
So what about your center truss that will not be against a post - toe nail to the top board?

Also the person in the middle with a 2x4 - how do you attach or keep the board from falling off the truss when raising? Rope or banding?

 

[blueriver]

BR,
So what about your center truss that will not be against a post - toe nail to the top board?

Also the person in the middle with a 2x4 - how do you attach or keep the board from falling off the truss when raising? Rope or banding?

I think your asking about the rafter between the poles ... at the 5' mark is where you put a "stub" block between the two top plates and nail the rafter to the "stub"

I use a 2x4 about 24" long nailed to the lift 2x4 to create a Y to assist in keeping the lift 2x4 in place ... a rope will also assist so the guy in the peak can help pull the rafter

 

[gabeancounter]

Thanks BR. That makes perfect sense. I was thinking it sure will be a pain to get to the top of the truss to unhook the 2x4.

Yes that was what I was wondering about setting the trusses. Thank you ... some times the obvious stuff is the hardest to figure out

 

[blueriver]

It will take a man on each side, one at the peak and one to "push or swing" The man at the peak can grab the top to hold it, the guys on each side can flush and nail the ends and the guy at the peak can nail the brace purlin.

A little trick while the rafters are stacked on the ground ... use a sledge hammer to align the ends and then mark the tops every 24" use a square and mark all the rafters ... then when they are in the air the 24" O.C. marks are already on the rafters ... no measuring in the air while hanging on !!

 

[gabeancounter]

Well..I received the first quote back from a truss builder about 20 miles away. $1560 delivered for 17 trusses. Guy has lost his mind. :confused2:

30' truss 1' overhang each side. 3' spacing. No finished ceiling. 4/12 pitch.