Sourcing metal for pole barn and quick discussion on design

[bob112]

Designing a building right now and metal will be a big cost. Curious where you guys are getting it? I will likely use 26ga PBRs with Kynar 500 or similar 40-50yr finish.

Also, I should add that I am an engineer and designing a tough building in that I want a large free span. Still pending some numbers here but will somewhere around a 5ply 2x8 post on 12ft center with tripled up roof trusses on 12ft centers. Purlins and gerts will be flush mounted with hangers to get maximum stiffness in all directions. Hard to deny the performance improvement mounting this way and I can add all the hangers on the ground.

For the poles, I will use treated and laminate via poly glue and screw, creosote or other coating on the part in the ground, 4ft deep, 18-24" holes on bed of gravel and creted in. I would like to add some uplift locks but not yet sure how I want to do that and not real sure they will be needed. Will have a concrete floor as well which will pour over the pole piers so that should lock them down.


Thoughts?

The roof trusses will take a LOT of engineering as they will be a 72ft free span scissor. They will have to have plywood solid centers. Build these onsite. Jig will take a minute to build.

 

[EddieWalker]

I use Mueller Metal Buildings Steel Buildings | Mueller Inc

72 feet is an impressive span. Especially for wood and a scissor design. Hope you post pictures of it, I'd love to see how you do it.

Eddie

 

[buckeyefarmer]

72' span will take some good engineering just on bracing.

 

[QRTRHRS]

Wish I had a photo of a barn/arena I was in several years back. Wooden trusses, 100 foot clear span in snow load country. Far as I know, still standing. I am thinking the spacing was four feet. The trusses were doubled 2x6 or 8's or so. Pretty amazing. In that area, the general thought was not that spanning 100 feet was doable or not but rather how much the trusses were going to cost.

Just seeing trusses that length or even 72 feet being shipped down the road is impressive much less sucessfully fabbing your own on site is impressive.

 

[bob112]

I might redirect this chat to insulation as I have not come up with good, economical solution yet. Obviously spray foam will do but I am not pay for that. I need about an R25 wall and R40 roof. Lots of guys just try to pinch R19 between the sheeting and frame but that just kills the deal. I need a good solution here, air/vapor barrier and all. Was looking to try and spray cellulose and cover with barrier but applying that barrier could really suck and not sure if cellulose would even stick 12" thick to a ceiling? Seems tricky! I hate working with glass...

 

[EarPlug]

Not only the trusses will take a lot of engineering but the installation will be a challenge.

Long (Attention) Span: Trusses Over 60 Feet Present Bracing Challenges | SBC Magazine

 

[MacLawn]

Canno' wait for the pics of this one, bob112.

 

[KennyG]

On the metal, you will probably need to find the best local supplier. In our area the best "off the street" price is from Menards, but the professionals get the metal from ABC supply to get better service and availability. If you get the contractor pricing, it should be competitive but no one gives big discounts these days.

That's quite an ambitious design. Any reason to go 12 foot on the spacing? That seems to add to the challenges.