New shop foundation? Poles in ground or out?

[ih555]

I am researching foundation options for what is going to be a 40x64 insulated shop with a 16 ft sidewall. I'm looking into all different types of foundations, not just poles in the ground. I am located in Minnesota and would prefer not to have poles in the ground. I have heard many stories of people who have rotting posts in their pole barns. I have looked at a pier type wet set foundation, pouring cement piers and using metal brackets to attach the columns. Anyone familiar with this type, pros/cons?? I have also read about perma columns, anyone have an opinion, pros/cons?? Thanks in advance for any information.

 

[Kevin Happke]

Give me a call and I will explain an Ideal to you .....call 320-468-6474 ...Kevin I am MN also

 

[bc]

Definitely wouldn't go with poles in the ground. Any fence posts I put in the ground I take the time to paint some roofing/foundation coat on the side and end that goes in the ground. A gallon of that stuff will last forever.

Concrete piers or a regular foundation and pour a floor at the same time would be my choice with plenty of rebar. Put a loop or bend a short L in one of the rebars so you can loop your J bolt to it (either wire it on or hook it under during the pour. Then you'll be covered when the next hurricane hits Minnesota.

Not sure anyone uses round posts anymore. Morton and others laminate treated 2 bys together with alternating seams. Depending upon the load factor and spacing I've seen posts with 3 or 4 2x6's or 2x8's laminated together. Makes it easier to attach to being square.

We have a local supplier with the metal forming machinery who can cut the roofing/siding to length. Talked to him about a steel frame 50x100 and he said it was cheaper to buy his metal and then frame up the sides with 2 bys like you would a house and it would be cheaper and easier to work with. I suppose metal studs could be used too. Then use wood rafters to span the 50'.

Food for thought.

 

[andy r]

I was concerned about poles rotting off as well. When I built my 48' by 88' a couple years ago I put the poles in a product call Post Protectors. I have really been satisfied. I think the tubes that fit over my 6 by 6 - 3 ply poles are made out of a plastic material similar to that used to line the base of landfills. Having NO joints down at the ground level like 1) having a pole set on a foundation or 2) using the perma-columns (concrete lower section) makes the building more resistant to the wind. It just really bugs me to see poles setting in dirt and water. Post protectors keep them dry. Highly recommend them.

 

[paul]

How do hey anchor the poles to the ground? That bit of plastic I would think is slick on both sides.

 

[john in la]

The weakest point of any building; especially one with 16 foot walls; is the junction where it connects with the ground.
In houses they combat this sheer problem from the wind by skinning the walls with OSB or plywood.
Most pole barns are not built to these standards as a metal skin does not meet the sheer performance.
So the best advise I can give you if you choose to use these options is to use braces; braces; and more braces.

Now with that said......
I live in a area where the water table is just below ground level.
In some places it is above ground level. We call this area a swamp.
We still drive wooden piles under slabs of every house for foundations.
We still build houses 8 feet off the ground on wood pilings.
We still build boat docks where the wood is sitting in salt water 24/7.
And we have none of these post rotting off problems at ground level.
In fact our fence post are more likely to rot from the top down.
Its the reason you see metal cans on top of fence post around here.

Our secret.
We still use CCA treated wood.
I know it may be hard for you to find but at least look for it.
If you can find CCA treated wood treated to 0.80 levels use it.
You will never regret your decision.
It will give you years of service and with solid poles give you the sheer performance.
CCA Pressure Treated Wood

 

[Bruce from Can.]

I built a 40x60 with 14 foot side walls 30 years ago for hay storage. Still straight and square. Pressure treated 6x6 in 4 foot hole, with a foot of concrete poured in the bottom of the hole. Concrete makes it easier to a-line the post during construction with smooth level base

 

[MarkB_MI]

If the posts are treated for ground contact and properly set, they should last a very long time. By 'properly set', I mean pouring a concrete plug at the bottom of the hole below the frost line and backfilling the bottom several inches of the post with pea gravel. Also, proper drainage is important, not just for post life but also to avoid upheaval and other water-related problems. The building site needs to be graded for drainage before the posts are set and the floor is poured.

That said, my brother used to erect post-frame buildings and liked to pour the floor first, then set the posts in brackets. It's just a lot easier to finish a concrete floor when there are no posts to deal with. But this was out west where the soil is dry and upheaval isn't a big issue. I think the concrete pier approach would be fine in your case, as long as the piers extend well below the frost line.

 

[BAnNC]

Unfortunately john, that CCA treated wood isn't available to those of us who live in the mountains. Just those near the coast. The newer stuff just doesn't seem to be lasting like the CCA did. Some decks make it 5 to 8 years before you have to look at changing out some of the treated wood.
For my part of it, concrete with a bracket on top of it for this area.

 

[Bruce from Can.]

I was always told that you either stay above the frost or go below, but dont mix. Which sounds like what you will do. Post in ground below frost, floor on floating pad above frost. So walls and floor could rise and fall differently. Can really mess up doors, etc. Maybe take a look at the way a bunker silo is built. The sight is prepared and a concrete footing 3 foot by 2 foot poured the length of the structure with rebar going horizontally and sticking vertically above the footing also. Then additional rebar is wired on to vertical pieces and sides formed and poured. If you built a 4 foot side wall from concrete, you could simply build a 12 foot stud frame wall on top of the poured concrete wall. With the floor poured between the footing before side wall construction began, you would have an excellent place to build wall sections before erecting them. And the four foot of concrete wall would be fire resistant if doing welding inside the completed building. You also would only need to side or line 12 foot of exterior and interior walls. The entire building is built above frost and no worries about rotting wood. Just a consideration

 

[Stephen Newell]

The poles in the ground are alright if they are properly treated. The problem is you can't tell by looking at them if they are done right or not. You have to cut about six inches off the pole to find out. Sometimes you can go by brand. Yellawood is the worst for just staining the wood with the chemical instead of actually pressure treating it. I use LIfeWood and have never gotten any pretend treated wood. Then there is the wood that says treated appearance. It should be used above ground and also in a fairly protected location, it needs to say For Ground Contact. The benefit of having posts in the ground is you can just pour a 4 floor right up to the walls. Building on top of the slab you would have to pour a concrete beam around the parameter. The only issue with that kind of construction is if the building is out in the open and you get some very high winds. Under those circumstances it might be better to use steel posts and insert bolts into the slab as you are pouring it.

 

[jhwis]

Build it on a slab. Neighbors have two sheds that size built with 16' stud framing. 2x8 for the wall. Not sure with prices now how it pencils out vs. pole construction.

 

[showcrop]

In the late nineties our town needed a transfer station. I drew up a conceptual plan and for a pole barn and we got some budgetary figures. The designers came back with some very high priced buildings. We had a meeting with the companies and I told them that what we wanted was a pole barn, and sent them back to rework. What they came back with and what we had built is a pole barn on a full foundation, with brackets attached to the top of the foundation. The floor is concrete, and the whole building is as straight and sound as when it was finished 23 years ago.

 

[Geo-TH,In]

At my age I don't think I'll live long enough to worry about my posts rotting off.

Sooner or later posts will need replacement. Good chance a strong wind will take pole barn down if post are rotten. Good reason to have insurance.


A company in Terre Haute advertises free concrete floor. They put down slab and attach poles to slab. I'm not sure that's stronger.

Building inspector requires posts to be 54 inches in ground. A footer only has to be 24 inches below grade.

I'm guessing 54 inches is to prevent wind from blowing build down, nothing to do with frost line, 24 inches. 16 ft walls will need a strong post to keep the wind from collapsing building.

I vote for the old way, post in ground.

A company in southern Indiana, makes laminate post.

After Arsenic was taken out of treated lumber, it definitely doesn't last very long

Is Arsenic still used to treat poles?
George

 

[andy r]

The post protectors come with small lag screws with a sealing washer. Can't remember how many lags are used to attach the Post Protector to the post. My contractor didn't use the lags. Since the top of the Post Protectors are about a foot above the ground the attaching fasteners for the grade board to the post actually make a good connection between the post and the Post Protectors. The outside of the Post Protector is formed at the bottom to help restrict withdraw from the ground. I am totally sold on them. The company that makes Post Protectors has a good website.

 

[RobCons]

I agree with John in la get cca treated lumber if possible. Big stores wont get it around here. Small lumber yards can order it under an agricultural exemption is how they explained it to me. If you have a telephone pole factory they use it also. I bought a bunch of 16 foot long poles awhile back, 6 - 8 inches diameter, and had the option of cresote or cca. They were $90 each.

 

[db4600]

Ive been read the replies. Theres a lot of good advice. The are many ways to skin a cat! Think of all the buildings youve encountered through your travels. Steel frame building can be large and have bolted connection. Yes even at the column/ slab connection. Some have footings and foundation. Some are floating. Think of some of the large barns and granaries that were built with a shallow foundation and no anchoring.

At Junkshow we have low heavy ground. We took down a 60x120. Partially because of rotting posts. Those posts were a lesser treated brown post from the late 70s. Weve also cut posts off that were heaving and poured a thickened, reinforced, with anchors for the posts and set it back down to straighten it. We also built a 40x60 floating slab last year with 2 rows of center posts set in angle iron connection with the exterior framed walls set on 6 inch block to keep the framing up from grade. There are many workable ways to erect the building.

 

[teddy52food]

Call John at 320 836 2284.

 

[2SteveWI]

Live in N Central Wisconsin, West of Wausau. Last year we put up a 40 x 30 Shop/Sugarshack. The Foundation is 5 inches of conrete with a thickened edge on outer 18 inches of slab. Has in floor heat tubing attached to rebar. This type of construction is common in this area. Local Amish Construction crew put up building on slab in 2 days using ladder type construction. Steve.

 

[Brian G. NY]

Morton and others laminate treated 2 bys together with alternating seams. Depending upon the load factor and spacing I've seen posts with 3 or 4 2x6's or 2x8's laminated together.
Food for thought.

Laminating in making a post assures the treatment goes all the way to the center. My 26 year old Morton building is built that way.
They drill a hole thru the post near the bottom and insert a piece of rebar as an anchor. They simply dropped unopened bags of Redi-Mix with a slit cut in them in the bottom of each hole and sat the posts on them. The holes are all at least 4 ft. deep (below frost) and where I had used fill to level the site, they went down until they hit virgin ground; 7 ft. in one case.
Worked out well so far and no sign of rot on the posts yet.

 

[ss55]

Site preparation for better drainage could make a big difference.

 

[DoubleO7]

(quoted from post at 07:26:07 04/07/21) Unfortunately john, that CCA treated wood isn't available to those of us who live in the mountains. Just those near the coast. The newer stuff just doesn't seem to be lasting like the CCA did. Some decks make it 5 to 8 years before you have to look at changing out some of the treated wood.
For my part of it, concrete with a bracket on top of it for this area.

False
CCA treated is only banned in residential construction and some public use construction.

Have you looked for any??
Look up Fortresswood.com made in NC and sold all over central NC.

 

[Traditional Farmer]

Have you checked out 100% metal buildings? I can buy an erected metal building for about the same price as the materials for a wood frame building,plus metal doesn't burn or rot.

 

[DoubleO7]

(quoted from post at 11:36:16 04/07/21) Have you checked out 100% metal buildings? I can buy an erected metal building for about the same price as the materials for a wood frame building,plus metal doesn't burn or rot.

x2
Exactly what I did.

Red metal frame
Pole barn siding and roof.

 

[bc]

(quoted from post at 09:36:16 04/07/21)

plus metal doesn't burn or rot.

And wood doesn't rust. lol

Buildings of any kind still need a lot of bracing to prevent racking. My old barn has a permanent lean to the north from all the tropical storm force winds we get in KS. The last month has been very windy. I see the wall move with those big gusts.

 

[john in la]

[b:654c4848f0]CCA treated is only banned in residential construction and some public use construction[/b:654c4848f0]


True
But I will admit it is not the easiest thing to find.

We have a place here that sells nothing but CCA lumber.
6x6 post and round telephone size poles. No problem.
But 2x4 and 4x4 can not be bought.
If you need 4x4's you need to buy a 4x8 and cut it in half yourself.
Smallest they have is 2x6 16 feet long used for dock decking.
And everything is Number 1 lumber.

Guy told me he does not want to chance competing with the orange box store and have the state question his sales.
So he does not stock any sizes the local big box store stocks.
By only stocking and selling sizes that can be justified as ag or mostly fishing dock material the state leaves him alone if he happens to sell to residential customers.

 

[CaseChev]

Had to re-do six rotted wooden poles in a pole building that we bought. Dug down and did perma columns with steel brackets on top to attach to remaining pole. Turned out great

 

[Traditional Farmer]

Neighbor has a metal shop put up about 1985 still in great shape.

 

[showcrop]

(quoted from post at 08:24:57 04/07/21)

(quoted from post at 09:36:16 04/07/21)

plus metal doesn't burn or rot.

And wood doesn't rust. lol

Buildings of any kind still need a lot of bracing to prevent racking. My old barn has a permanent lean to the north from all the tropical storm force winds we get in KS. The last month has been very windy. I see the wall move with those big gusts.

bc, get you some barn cables. I bought three sets last year. Pull the old barn back into plumb.

 

[Geo-TH,In]

Before I built, I went to assessor and asked about property taxes. The taxes on a stick build building was crazy. A post beam is the cheapest property taxes. Taxes is based on square feet, not cubic feet. So I made my building 14 ft tall so I could add a second floor to store things and not take up floor space..
George

 

[Texasmark1]

Obviously I'm a Texan. I had a pole shop built with poles in the ground and after construction had a slab poured inside which really was not connected to the pole concrete...called a floating slab. I didn't think a beam, like used in house building, was necessary due to the load I anticipated on the floor.

I'm on top of a hill and over time the soil moves. It causes problems. In retrospect, and my suggestion to you, is a slab like would be used for a home construction, with beams and embedding steel plates, anchored down in the slab with the top flush with the surface of the slab would be the place where the building supporting elements were to be welded for support. To that you would add any special Northern Tier requirements that we don't have down here. In short, no I wouldn't put the poles in the ground.

 

[C.Amick]

On my last pole shed we buried the posts after dousing them with wood preservative and wrapping them with shrink wrap. That has been about 20 years ago. No problems yet. How old are you? I guess as long as it out lasts you, it should be good.

 

[John in Mich]

My son just got his permit approved for a 40x64 barn. He plans to use the design that you describe. He lives in Manchester, Michigan.
My strongest suggestion to him was to be sure that the elevations direct water AWAY from the structure.

 

[Hdonly]

I'll let you know in about 20 years. I think I read about every method possible. I ended up digging the 4' hole, concrete pad in first, then post and packed dirt back in the hole. I'll see what happens.

 

[bc]

Got to thinking, I used CCA treated round posts on the shed we attached to the barn 40 years ago. Some are ok but there are two I noticed have rotted through at the surface in a corner where the drainage runs by them. I can fix by digging a new hole along side and sister in another post next to the one that is in concrete.

I have replaced a few CCA fence posts that have rotted off at the top of the concrete. Not so much a factor with a braced up building, but for wood fences with cedar planks I've found that in this clay in the area dries up in the summer with cracks so big you can stick your hand in them. Then the wind would blow the fence around and the posts in concrete would wallow out the hole they are in. Any new fence I put in now has the posts coated with roof/foundation coat, few inches of gravel in the bottom, and then I back fill them with sand. The sand stays packed around the post and during the wet dry cycles of moving clay, the sand fills in as the clay dries up. When the clay gets wet it just packs the sand in tighter. After a few years I throw some more sand around the post as it moves in to the clay. Also changed post spacing from 8' to 6' and with an 8' long post I only need 5' above ground (for a 6' tall fence) so that puts 3' in the ground below frost depth. Those fences don't wiggle an inch even with a fence facing a south wind blowing 30+ mph.

One of my pet peeves is all these steel building companies that put up their buildings right at ground level and don't do anything for drainage. I've seen some build into a depression or low spot.
Houses have to be on a foundation at least 12" above ground level to help keep termites out and control drainage. I'd do the same as a house for any steel building.