Pole barn construction technique

[Ryan03]

I am in the middle stages of planning my new pole barn/shop. It will be 32x48x12. I am familiar with conventional post frame construction. Recently, a method of framing I am not familiar with was suggested to me. This method uses shorter post, around 6ft, with only 2ft or so above grade, then header boards and sill plates are attached to the post above grade creating a knee wall of sorts. The remainder of the wall section is constructed of 2x4 studs 16 on center and placed on top of the knee wall to form a wall section. I was told this system aids in the finishing of the inside of the building, and can be cheaper when all is said and done if you plan to finish the inside of the barn, which I do. Can anybody tell me what the name of this type of framing is, as well as pro's and con's, cost vs conventional pole barn.

I already tried doin a google search, but don't realy know the term to search for. Any help would be appreciated. Thanks, Ryan.

 

[quicksandfarmer]

I think I'd call that a post and pier foundation. If I was only going up 2' with the posts I think I'd use Sonotubes and concrete instead of poles.

I'm not an expert but I have an opinion.

 

[MarkV]

My first thought was that you would be creating a hinge point that would not be as resistant to wind load as poles going from ground to roof. Then I thought with the upper section being stick framed you would likely be sheathing the walls with ply or OSB and that might overcome the hinge affect.

How about some more detail on how you plan to cover the barn.

MarkV

 

[Iplayfarmer]

I don't know what you'd call that type of construction, but I'm using it on a part of my workshop build... http://www.tractorbynet.com/forums/projects/239349-root-cellar-remodel-split-level.html

I have a 10' X 10' Root Cellar, and in order to build a 12' X 16' shop over the top of it I'm using poles to support three of the corners. Once I get the subfloor built I'll go the rest of the way up with stick framing.

 

[Ryan03]

My first thought was that you would be creating a hinge point that would not be as resistant to wind load as poles going from ground to roof. Then I thought with the upper section being stick framed you would likely be sheathing the walls with ply or OSB and that might overcome the hinge affect.

How about some more detail on how you plan to cover the barn.

MarkV

The barn will be sheeted with osb, then vinyle sided. Roof will be a asphalt shingle. Doors will be one 16 x10, and one man door. The minimum required roof snow load capacity in my area is 35. Roof will use free span trusses 16 inches on center.

This is a building technique that has been realy catching on in my area the last 5 or so years. I was able to look at a barn today that is being constructed very similar to the one that I am proposing. This one used 4x6 post 36 inches below grade, and one foot above grade. There were 2x12 header boards on either side of the 4x6's, then a 2x8 sill plate on top of the header boards. Conventional 2x4x12 stud walls were built on top of the sill plates. The barn I looked at today will get a 6 inch thick concrete floor, and when finished, the concrete will be level with the bottom of the sill plate. The header boards that the sill plate rest on will serve as the edge forms for the concrete floor, and the floor will sit on 6 inches of #8 lime stone.

I realy liked what I saw. Especialy the way the floor will come right up to the stud walls. Looks like a real sturdy design. If I go this route, I may opt for 2x6 stud walls over 2x4.

 

[KentT]

I realy liked what I saw. Especialy the way the floor will come right up to the stud walls. Looks like a real sturdy design. If I go this route, I may opt for 2x6 stud walls over 2x4.

2x6's on 24" center are about the same cost as 2x4's on 16" center and provide a deeper wall space for either insulation or recessed shelves...

 

[piller]

Sounds like an interesting building method. What is the spacing between the poles in the ground?

As someone else mentioned my thought was about bracing the walls against wind loading, the walls will be braced at the corners naturally, how about the top of the 12 foot walls, in the middle of your 48 foot wall? Is there a wide top plate that provides stiffness, or perhaps braces to your trusses?

 

[Ryan03]

Sounds like an interesting building method. What is the spacing between the poles in the ground?

As someone else mentioned my thought was about bracing the walls against wind loading, the walls will be braced at the corners naturally, how about the top of the 12 foot walls, in the middle of your 48 foot wall? Is there a wide top plate that provides stiffness, or perhaps braces to your trusses?

I did not get a chance to look at the top wall bracings, however the barn belongs to a freind, and I plan to stop in again this week end to take a real good look and maybe some photos. Here is a link I found with this type of construction. It looks like this is a cheaper product due to the fact that they are only using 2x10's and a 4 inch floor that does not come up to the sill plate, but it gives you a pretty good idea of how this is done.

http://www.thebarnyardstore.com/custom-garages/foundation-options/39-posted-foundations

 

[ALKY]

I built an addition on my mobile home similar to this.6x6 3ft inground to floor grade.floor deck like a 2 story,with stick built walls shingle roof. Easy and code inspector liked it!:thumbsup:

 

[BeezFun]

I like this style construction. I'm getting ready to put up a pole barn garage, this has the advantage of letting me use framing techniques I'm familiar with as soon as I get above grade. And more traditional truss spacing on top plate type of design rather than heavy trusses on each pole or on ledgers. Thanks for the info.

 

[flusher]

Called a "buried post footing" in the decking trade

The Buried Post Footing - Decks.com

Personally, I'd just as soon use concrete pony walls that extend 24" above grade. No rotting post concerns that way. The fact that you want to stick build your pole barn indicates that you've decided against pole frame construction and that decision would point me toward concrete footings and forget about buried posts altogether.

Good luck.

 

[droptop]

I really like the method that Morton uses to set their post. Makes setting the posts a one man job. They use 3 treated 2x6's that are nailed together and have a metal stilt on the bottom to lift the bottom of the post about 6" off of the bottom of the hole. With the post only about 7 or 8' its easy to handle. They are braced and concrete is poured in the hole which goes around and under the post. With the hole backfilled, the bottom board is attached which establishes grade. All of the post are trimmed to the same height with a 18" stagger between the 3 boards that mates with the top section of the post which gets nailed to the bottom. It makes setting the post quick and easy.

The link below show a lot of good photos.

36x72 morton barn build - The Garage Journal Board

 

[mattbatson]

now, wont the wood just rot over time?
Wouldnt it be better to do sonotubes of concrete, then simpson or other bracket to isolate the 6x6 from the concrete?
I only ask as I am planning on building a crawl space foundation which I will be mounting a quonset hut on top of

 

[rambler]

Roof will be a asphalt shingle.

Ick. Why ruin a good long-lasting building with a poor roof? Go tin. Ick.

I too like the concrete pier instead of the short wood post in the ground.

Pay attention to the joint on the knee wall, as others are pointing out, that needs to be braced right to handle wind-stress on a large wall such as a shed.

--->Pau

 

[davedj1]

I see no difference in the buried post method and standard framing on a slab as far as the "hinge" joint you are talking about. As long as the trusses are braced properly the walls will respond in the same manner as any other wall. Picture a house with a full foundation, first floor deck, then 9' or taller walls with trusses, we have never worried about a hinge joint there.
I have never used the Morton method but have often thought about trying it. I think you would have an easier time getting them in a straight line and plumbing them. The last two pole sheds I built were 6x6 posts in the ground 4' sitting on a bout 12" of concrete.

I guess if I knew for sure I was going to finish the inside I would go with the buried post method with conventional framed walls on top. but on the other hand, why not pour an Alaskan slab and just build on it?

 

[LD1]

I see no difference in the buried post method and standard framing on a slab as far as the "hinge" joint you are talking about. As long as the trusses are braced properly the walls will respond in the same manner as any other wall. Picture a house with a full foundation, first floor deck, then 9' or taller walls with trusses, we have never worried about a hinge joint there.

I was thinking the exact same thing:thumbsup:

As far as cost and ease of finishing, IMO you cannot beat a traditional post framed building.

When I built mine, posts and nailers were cheaper than a stud wall per foot of wall. So that is +1 for post frame.

Post frame is also easier IMO to wire and finish....Well, finishing would be about the same, only the "studs" are running horizontal instead of vertical. But still, on standard spacing, you can still finish with interior sheeting the same way, and the insulation would run horizontal instead of vertical. But as a benefit, you dont have to drill all the studs just to run electric. You can run the wire along the top the nailer (horizontal stud), and when you come to the post, you dont even need to drill the post, because there is the airgap between the post and your exterior sheeting. so +2 for postframe.

And since the posts carry the load and not the entire wall, there is no need for HUGE headers where garage doors and what-not will go to distribute the load. So +3 for post frame.

I really cant see any benefit to a tradition stud wall vs post frame on any single story structure. Infact, if I were building a single story house with no basement, I would probabally do it as post frame.:thumbsup:

 

[EddieWalker]

I don't get it, or any advantage to going this route.

The advantage to pole barn building is the ease, speed and strength of the poles in the ground being part of the walls. There is a lot of strength in this method that allows a minimal amount of material to be used. Pole barns have been around forever, they are proven and they are just about the most economical way to build a structure.

If you want to use stick framing, then pouring a footing and framing up from that would be the way to go. There is no advantage to setting poles in the ground and only coming up two feet, then stick framing on top of that. More work, less strength, without any real savings in materials.

Idealy, pouring a full slab and building up from there would be the best way to go if you can afford it, but that's the big difference between pole building and stick building. Both will give you the building, but one way is more affordable then the other.

As for finishing off the interior, what do you want to put on the walls? You can cheaply and easily install purlins on the inside every two feet and attach plywood or OSB to it for a very nice, solid, interior wall. 5/8 sheetrock works great on 2 ft centers also. You won't spend very much on the extra purlins, all your expense is going to be on what you decide to use for the interior siding.

Eddie

 

[Little_Grizzly]

I'm with Eddie on this one. Why go through the effort of digging the post holes only to leave two feet of pole above grade? The disadvantage (if it can be called that) of a pole barns is the rotting of the poles below grade. The advantage is the simplicity and lower cost of the main support being the same piece as the wall member.

With this method you get the disadvantage with none of the advantage. Why not just fill that hole with concrete and have a nice strong and relatively cheap foundation?

 

[droptop]

now, wont the wood just rot over time?
Wouldnt it be better to do sonotubes of concrete, then simpson or other bracket to isolate the 6x6 from the concrete?
I only ask as I am planning on building a crawl space foundation which I will be mounting a quonset hut on top of

The real key is using wood that is heavily treated for ground contact. The new "treated" lumber that you get at most stores is not suitable to for posts. I know the lumber that Morton used to go under ground is treated to 0.8 pounds per cubic foot of Chromated Copper Arsenate (CCA) to prevent decay.

Three-Member-Laminated-Pine-Columns

The other advantage of pouring around the post is that it is locked in place to prevent pullout by the stilt on the bottom of the post.

In_Ground_Laminated_Column_In_Concrete_Footing

 

[BeezFun]

If you want to use stick framing, then pouring a footing and framing up from that would be the way to go. There is no advantage to setting poles in the ground and only coming up two feet, then stick framing on top of that. More work, less strength, without any real savings in materials.

I can think of several cases where you don't want to pour a footing. One is near mature trees that are of high value. Digging a foundation will almost certainly kill them unless you try to do root pruning. If you have utilities under the location of the building, it's easy to put in piers/posts to avoid the utilities and still support the building, almost impossible to do with a footing. If you have an underground spring it can cause a lot of problems to trench into it for a footing. My friend did this and had to reroute the spring around the building location, big bucks. Another issue is the type of soil, if the location is on top of a morraine or some area with large difficult rocks, the less you dig the less hair you'll pull out.

It's also not clear why you say piers offer less strength- it depends on the soil and how they're designed. Sky scrapers are only possible because of isolated pier techniques developed to avoid the need for continuous foundations. I think it's not possible to categorically declare one construction technique better than another without considering site specifics.