Your thoughts on Pole Barn general construction and kits

[Wa11banger]

We bought a 20 acre property 9 weeks ago 13 acres mature woods and 7 acres in the middle cleared. Unfortunately the previous owner used it as a dump site and it has taken this long to get it cleaned up.

But, now that it is all cleaned up I am looking at putting a 30'x50'x12' or 30x60x12' pole barn with 12' wings on each side (eventually) up to house my tractor, RV, toys and tools, etc. To help with costs and paying cash I also am trying to do it in phases. I checked several places and priced out having phase one built for me and it was beyond my cost constraint $11k providing all materials and labor. So being fairly good with tools and moderate experience with construction I started pricing out building one myself. I have never built anything like this, my building skills are associated with demoing a wall, adding a wall where one wasn't before, and base framing a house when I was way younger and back then all I did was what I was told. I do have all the resources to prepare the site and lift the trusses regardless of which type.

Conditions and location information:
Property is in Southern, Tn. not very snowy although we get some every year usually around 6" but up to 12" at times all for very short durations. Usually breezy at this location but not terrible. Occasional high winds due to storm activity. Enormous amount of rock (huge, big, and small under my topsoil).

Phases of build I am considering: (I believe I can pull this off over the course of 12-16 months after basic structure is up)
1) build basic structure no sides open all the way around
2) Gravel inside to start
3) Pour pad after construction ( not sure how to get this done but I am sure the company that will do it has before)
4) Put up sides and back leaving entrance open (2x6 construction with metal siding)
5) add 12' wings they will remain open except wall of main structure
6) close in entry with large roll up door and man door

So I had a few questions

1) 6X6 PT posts 4'bg in concrete (concrete extend 6"ag). I think this would be the strongest but many I have looked at are bolted to concrete pads. I don't want to get into the laminated 2x6 vs 6x6 debate, just want to know if there is significant advantage to keeping posts above grade or do I lose to much strength doing so? Not sure of frost heave but neighbor says we have rock farms and I have areas with high surface rock content.

2)I see plenty of each type of truss in the barns I find interesting and want to build like. But in the metal vs. Wood debate is cost the main driving factor between them? One reason I was leaning more towards metal was open center for added height clearance in the middle. A driving factor for 12' sides is the middle is near 15' clearance to the cross brace in the center, where all wood truss designs I have seen are straight across.

3) I was thinking 10' on center for the poles but have been reviewing several barn posts here and trying to understand the controversy between that and 9' due to metal sheeting sizes.

What do you think about these kits online or CL? I have found one that will sell me a 12' wall, 30' wide x 50' long kit for $4k + delivery ~$220 The kit consists of 16' 6x6 posts 10'oc, top plate, metal trusses 10' oc, truss cover metal for gable ends, soffit metals, all hangers and hardware to complete a basic open wall pole barn. Is this a fairly good price as they seem to be all over the board with no real "normal" center number? Anyone with good, bad, or ? experience with this type of kit?

Thanks in advance TBN'ers

 

[doxford jim]

Can't help you with the build itself, but my research showed that wooden 6x6 treated posts do not last long when buried in the ground.
I built my 28x26 car port and used sona tubes full of concrete and 3 lengths of 5/8" rebar to put the posts on. I built with the concrete sticking about 16" out of the ground - where the 6x6 posts bolted on. Your part of the country may be different, but up here in Canada, it isn't unusual to see the post bases above ground (very common).
HTH

 

[GManBart]

I'm not a big fan of putting the posts below grade. I had to go with a poured foundation on mine, so I used Sturdi-Wall brackets on top of the foundation. If I was able to go with poured columns, I would have used the wet-set style brackets like these:

https://www.permacolumn.com/wet-set-models

 

[Dr_Zinj]

When figuring snow weights, take the highest recorded snowfall for your area, and double it. That becomes the minimum standard for you to build from. Ditto if you get volcanic ash fall. Anyone remember Mt St Helens?

As for winds, F3 tornadoes go up to 205 mph, F4 260 mph, F5 up to 318, anything over F5 you may as well forget structural survival unless it's buried flush with the surface. The worst tornado Tennessee ever had was an F4.

I live in New England, buried wood decays, corrodes, or gets eaten, even railroad ties with creosote pressure driven into them. And buried metal doesn't fare any better unless it's pure gold, which isn't a building material, even if you could afford it. Rock or concrete for buried footings and walls, and treat the concrete because the soil is acidic and will eat it too. Tennessee is probably very alkaline due to all the limestone.

 

[Wa11banger]

Thank you all for your comments..

Gman - I had thought about using sonotubes for my concrete pours just so it was easy to make it 6" ag so when I went to poor the pad later it was easier.. So maybe going sonotube and those beefy post mounts would do the trick. I just wanted it to be as sturdy as possible due to the quick storms we get up here and as you may know the devastating tornados we get in this area.

Dr_Zinj - thanks for the loading information I will keep that in mind when I talk to the kit mfg again or if I decide to go wood rafters and see what they are rated to

 

[doxford jim]

Another item worth considering is the Bigfoot form

Concrete pier footing forms save time, save money on decks, renovations, new construction

This can be used with the sono tubes and makes for a very solid foundation and bearing load. Add the bigger post mounts above and I think you have a winner. Not cheap but very effective.

 

[Wa11banger]

Thanks jim. I will think on that. Im leaning towards burying them in the concrete and over building the eaves to ensure they stay dry

 

[rutwad]

Buy a metal building, get the plans, and have a slab poured with anchor bolts in place. Metal building will go up much faster and easier.

 

[Wa11banger]

Thanks for that advice rutwad but I am not particularly concerned at this time with speed and easy. I want to make sure it has longevity and I can build it in stages. But I appreciate your input. Plus I just like the look of wood except for the roof. I want that to be metal.

Due to the responses so far though, it seems not much experience out there with the ready to build kits offered these days. If I go that route I may have to create a thread about it here

 

[GManBart]

Thanks jim. I will think on that. Im leaning towards burying them in the concrete and over building the eaves to ensure they stay dry

A potential problem with that is that concrete acts like a wick, and any moisture in the soil winds up on the post. Even if the ground isn't getting rained on, it will easily travel the couple of feet from the end of the eaves. I think some folks are coating the post, or wrapping it with something before pouring the concrete around it. Evidently, new environmental laws have changed the chemicals used to treat most wooden posts, and the new ones just don't last nearly as well. I do recall a long thread on just posts, and it is sometimes possible to get posts with the older chemical treatment, but it can be harder to find them. The older chemical was CCA, and is supposed to be available for industrial, or agricultural uses, but you'd have to call around to see who can get them.

Having to worry about posts rotting due to contact with the concrete, or moisture in the solid, the possible need to coat the posts, or go through the trouble to get a particular kind of post would push me away from setting them in concrete entirely.