Pole Barn, Needs Footing?

[Piston Slapper]

I am starting to build a 30x30 Pole Barn with a concrete floor. Went to codes office to get permit for building and to verify what they wanted vs how I was going to build it. They said you need to pour a 12"x12" footing. After leaving and thinking about it the more it didn't make since. How would you pour a footing for a slab for a Pole Barn? Isn' t this the point of one being framed this way was to eliminate this? If you did pour a footer it would be broken by the poles themselves because they are so deep thus preventing the footer from doing its job, wouldn't it? Unless you put your poles on the outside of the slab, then back filled the space between your footing/slab and poles. That would stink!



My thinking if the poles being 4' in the ground with 10' exposed for the walls would be supporting the weight of the building. Why do you need a footer for the slab? It is gonna primarily be a workshop with some access from my vehicles for maintenance. I was gonna put concrete or cruched rock in the bottom of the holes for a footing for the poles. Then fill the inside(center) w/ 4" - 12" of gravel to level the slab and pour a 4" monolithic slab with a turndown. Would this not suffice? The spot I am building on has about 18" of fall from one side to the other. I am going back to the code boys to check with them. Just wanted ya'll opinions.



Muchas Gracias,

Gap

 

[Rebel_Horseman]

I recently worked fro a nation-wide company that specialized in post-frame buildings, especially storage buildings such as you are talking about. Only on special occasions did we use footings. Our standard method of construction is a 5x6 or 5x8 laminated column placed in the ground 4' (larger buildings required it to be in the ground deeper). In the bottom of the hole we placed a 50# sack of concrete, inserted the column, then added another sack of dry-mix then backfilled with dirt. Using this method we warranted the building against wind load and snow load damage for 5 years or more. There should be no reason you would need a continuous footing around the building. If you would like more detailed info PM me and i'd be happy to fill in the gaps.



Brian [><]

 

[Piston Slapper]

Thanks, Rebel



This is what I was thinking. Gotta Love Paintbrush...

 

[illflem]

The continuous footing is for the slab, the poles are a whole different story.

The depth of the footing is based on your local building code (or common sense) which is based on how deep the ground freezes. If the footing isn't deeper than the depth of the frost line the slab will heave and crack.

Feel good about a 1 foot deep footing, in Montana it's 3 feet minimum. If your ground doesn't freeze forget the footing.

 

[Piston Slapper]

Continious footing.

I still don't understand how you can have a continous footing with the poles in place. Especially being as they wanted two rows of rebar in the footing too. How can this be if the poles are even with the outside of your slab so you have a smooth surface?



I still don't see the need for a continous footing anyway with the poles in place. A monolithic should be sufficient.



Thanks for ya'lls replies. Our frost line here is a whopping 16", So i'll guess I'll be that deep...

 

[TPCDrafting]

Did they specifically say a "continuous" footing or a 12"x12" footing as you originally stated? I'll bet they want a pad at the bottom of the hole, like a reverse mushroom. The building dept. should have details drawn up to help you out. There is no need to have a cont. footing under the poles, it wouldn't do anything. For the turned down slab edge, as long as the soil isn't expansive, it's not necessary. If it is expansive, be sure to put expansion material between the slab and your columns/structure. Thus the slab can break dance if it wants and won't interfere with the structure of the barn. Include 2-3 bars in the slab at a 45 deg angle to the corners of the poles kind of like: //o\\

The most likely place for the slab to crack is off the corners of the poles, if you place these bars in, cracks are less likely. Also, spend the extra $$ and put fibermesh in the mix. On my soil, I pour 4" with 8" thickened edges, 3000 psi mix, a little on the wet side per weather conditions.

 

[ropinfool2]

Last year I built a 36 X 48 pole barn with 16' ceilings. I had it permitted as a barn. After it passed inspection, I added the cemet floor, used fibermix, no rebar, and poured from wall to wall. Turned out good, finished a little rougher than I wanted but it was ok. Made 24 x 48 shop out of it with 4 12x12 stalls on the end. Oh it was built by licensed contractors. After it passes inspection the homeowner can legally do just about anything to it he wants! John

 

[illflem]

I wouldn't think the frost line is that deep in Tenn but I also think of it as the tropics down there. Only times I've been there is in the summer, 90° and foggy.



The way we did pole barns with slabs was to do the posts first and only fill the hole to about 4'' below the level of the bottom of the slab. The footing's rebar then rested on top of this on the side of the post facing the inside. Actually made it easier because the rebar only needed to be supported once in the middle in-between each pole. The rebar shouldn't touch the pole because if air can get to it rust can start and eventually rust out all the steel in the slab.

 

[Piston Slapper]

They said "continuous" footing to support the slab. I don't see how you can have a "Continuous' footing for a pole barn. The poles are in the way. Further, I don't see the need for a footing for the slab. It is not barring any weight of the structure, just what you put on the floor. I can see a footing for the poles, which I had planned to do.



I was wanting to pole frame and metal side the building. Put in crusher run and compact it down, then just pour it wall to wall about 4". Would this not work for a work shop w/ intermittent vehicle maintenance as needed? This is what I am going to take back to the code folks and see. Not trying to skimp at all. Just trying to do this on a budget. Don't want to overkill anything and investment double the money in a slab if I don't "need" it. What ya'll think??

 

[esommer2500]

You might contact several contractors in your area to see how they do it. While you're at it, have them price the building, you might be surprised. Having a (good) contractor do the work is often less expensive than trying to do the work yourself, especially if you haven't undertaken a project like this before.



I'm not trying to talk you out of doing it yourself (if in fact you were), but I have spent a lot of time finishing projects that a homeowner has started, thinking they were going to save money doing the work themselves. It often ends up costing much more in the long run. Contractors often get reduced pricing on materials, and already have the tools and tricks of the trade. FWIW.



A good concrete crew will do wonders for your floor, and will know how to set it up for your area and climate. We always cut the doors down about 3/4", ramped 16" into the slab, to make sure that even if the overhead door doesn't seal properly, water doesn't run into the building. I also recommend cutting the slab with a Soffcut saw, cut joints are easier to keep clean than jointed control joints. Also remember that concrete is only as good as the foundation it's placed on. Good compaction of the aggregate is critical. I could go on and on, if you have any other questions feel free to PM me.



Sorry so long.



Eric

 

[Rebel_Horseman]

Here's how we build our structures. Imagine a wall with 5x6 columns spaced at regular intervals. All columns are embedded in the ground the same distance, typically 4' unless it gets really cold. At the bottom of each hole are 2 50# sacks of concrete, one that the column sits on and the other surrounding the column. Each column has a 12" piece of #4 (1/2") rebar through it. Now, at your finished floor elevation there is a 2x8 running continuously around the perimeter of the building nailed to each column. This piece of wood runs on the outside of the building. When concrete is installed it is poured flush with this piece of wood which will then flow around each column.



Using this method we warranted the building for 10 years against wind load damage with no wind velocity limit and 50 years against snow load damage with no weight limit. A few times the local building inspectors gave us grief but when we explained how the building system worked together they passed the project.



Brian [><]

 

[Piston Slapper]

No harm taken, I am a serious do it yourselfer. I love contruction. I have thought about quiting my computer job to build houses I like it so much. I have built our last two houses myself. Framing, plumbing, wiring, drywall, the works. I am a one stop shop. Really, I usually am dissatisfied with contractors work. I always feel as though I would have done a better job and it would have been cheaper. I have learned that 1/3 of the cost of your typical project is materials and 2/3 is labor. So, thats what I do. I just do it all myself. I have about every tool I would need, I just haven't had the luxury of building a pole barn before and pouring a slab. I enjoy the work, it's my hobby. This is why we have sold our last two houses, just to build another. I have something most people don't..... time. I only work 3 days a week and am not afraid of work. I am one of them rare people who actually enjoy sweating and sore muscles !





I have gotten a few quotes for turn key outfit and some for just the slab. I can do the slab myself for 1/3 -1/2 the cost of hiring it out. I may still hire out the slab pouring, but it is killing me to think of pay'n $3,000-$4,500 for what I can do for $1,500 for materials.

 

[midwestdually]

another question for you is... . why are you building a 30' by 30' pole barn?? why dont you stick frame it?? alot better to be built this way ... . most places dont require footings unless it is over 1000 sq. ft. just a thought... lay the slab... run a couple rows of block around it and build your 10' walls... insulate it and you are good to go... . no post holes or bags of concrete to mess with no worries about a footing... . just a thought... . just seems like a pain in the ass to build a pole barn that is basically a garage... .

 

[fbaurley]

Wood in ground = rot. Personally after having several pole buildings over the years with rotten posts. I would not put posts in the ground on a building that i wanted to be around for more than 25 years. If you are going to pour a concrete floor any way, then whe not just pour a monolithic slab, with a footer dug down ( or trenched) around the perimeter, and anchor your posts to the slab with concrete anchors and strap iron. This tyle of setup will last for ever. If you decide to put posts in the ground, the code is probably refering to a 12in by 12 in pad in the bottom of hole. Also when buyinmg posts make sure to get at least . 6 lb/cu ft retention of preservative. Most stuff you buy is . 4 and is not rated for in ground, just ground contact.

 

[Piston Slapper]

I think it is cheaper, easier, and faster to build a pole barn. NO sheathing, NO decking, NO shingles. It's not a preference of one or the other as much as it is a cost factor. Metal sided pole barn is cheaper to build than a stick framed vinyl sided structure that has to be sheathed and decked, then sided and shingled. Half the wood involved in framing a pole barn. Trusses every 7'6" vs 16".



Why are there all these metal implement sheds on farms across the country? Cause they are the most bang for the buck!

 

[Rebel_Horseman]

Originally posted by fbaurley

Wood in ground = rot.

Not if you build the building correctly and use quality materials. The posts that we installed in the ground had . 6 retention. All wood items that came in contact with the ground in any way were treated this way. We then had a 3' tooth-joint 3' above grade then switched to untreated wood. Using these materials and methods we had a warranty of 50-years against decay. Rot will only occur where there's not enough treatment, or only partial treatment, such as in a solid 6" square post. Our posts use 3 2x6's all of which had 100% absorption into the wood.



Just a little tid-bit.



Brian [><]

 

[illflem]

I agree with you, but of course I'm a farmer.

The problem with pole barns is when someone wants to use them for something other than the original design.

When you start insulating and adding interior skin you're almost better off to tear it down and start over.



I've built pole barns both ways, with the posts set three feet in the ground and with metal brackets on top of the concrete. Prefer the post in the ground method for structural integrity especially if there are no walls. With the brackets you need a bunch of angle bracing.

 

[QRTRHRS]

The builder that I used drilled his holes, dug them out, tamped them (did not take much tamping in hardpan) and placed 16" x 8" round precast concrete pads in. They braced the . 60 retention glulam posts and tied it all together square then poured in concrete around the posts to grade. The roof is post supported with collar ties. I had the center aisle and my service rooms poured. They nailed 2x's to the horse stall side of the posts, put down 4" of stone and poured a continuous slab. The slab envelopes the posts on three sides. It does not meet the concrete poured around the posts. They cut expansion joints like mentioned already. Frost line here dictates four feet to the top of the footer.



Around here, pole construction is used for anything and everything. Money and future changing needs is why. Ask yourself how long your going to live there and is the extra expense of stick built going to make a difference if you sell and move?

 

[esommer2500]

Slapper:



Glad you enjoy doing things yourself, and you're right, time is the biggest luxury on a projet like this.



If you're planning on putting down some mud sometime in January, shoot me a PM. I might have some free time to take a road trip through TN on my way down to SC.



Eric

 

[midwestdually]

no sheathing... use the metal tin as your outside sheathing... . 24" on center not 16" and there is a reason why there are professionals and then there are YOU... sorry... but i cant stand the guys that want the top quality product for basically nothing... . a reason why structures like the deck in chicago fell down and killed many people... if you are a cheap *******... dont call me... . it will never be good enough for you anyways... . good luck with your project and enjoy it while it is up!



welcome to the discovery channel and better homes and gardens people... . everything can be done in one half hour and it is always done on time and to the T





good day:-{}