Pole building foundation question

[EddieWalker]

I would never ever use any soil as a fill for a concrete foundation because of the high organics. The best choice is a select fill, which has been washed and is free of organics, and is fine grained trending mostly to a silt sized particle. You typically find these type fills in river bends where large and now exposed silt bars are deposited and the naturally washed and recovered fill is sold by truckloads. It is relatively dry to visual eyes, but it does retain water by surface adhesion on each silt particle, giving a perfect moisture content for the overall select fill.

Compaction of such a selected fill occurs very well using a typical 10,000lb tracked skid steer. But you should spread and compact with each truck delivery, not dump say 20 truck loads first and then spread and compact all of it. Even wheeled vehicles struggle greatly when that occurs, resulting in uneven compaction surfaces. Usually you can build such a foundation as fast as the trucks deliver, or about 1 to 2 days.

We are night and day apart on this. For fill to compact, it must bond to itself. It must hold moisture, and it must be a certain level of moisture for it to compact.

Clean fill is the soil that does not have top soil. Top soil is where leaves and plants have deteriorated and are breaking down. Here in East Texas, where I live, we do not have top soil, just a layer of organics that are cleaned off. How deep the top soil is depends on location, but once you remove it, the clean fill is the dirt that is found under the top soil.

Every machine with tracks is designed to float over the ground. It has the very minimal PSI possible. It is the very worse machine possible for compaction. Using a light weight 10,000 pound machine doesn't even make sense.

 

[EddieWalker]

Ok I gotcha. Sure, you can anchor 6x6 posts atop a foundation and build a normal style pole barn that way. But I have to question why - you are making a hinge point where the posts anchor to the foundation. Just seems less sturdy. Whereas when you stick frame, which it sounds like we concur on, you have an entire 2x6 bottom plate repeatedly anchored into the foundation, and a much more sturdy box frame of a building constructed atop it.

Yes, 2x6 stick framing typically costs more than a pole building, but it's primarily because of the need for a full conventional foundation. You are doing that anyway, sounds like. I would price it out to see how much building your side walls out of standard 2x6 framing would cost, in comparison to buying expensive 6x6 poles that are now somewhat tricky to anchor to the foundation. You can still use the same roofing trusses atop a standard 2x6 framed wall. Only difference is, your building will be stronger, easier to insulate, wire, and so on.

But I would also still consider just making a big dirt pad that is somewhat larger than the building size, properly compacted in 6" lifts, and then just put your poles in the ground normally. I bet this would be cheapest overall.

This is very good advice. If you are going to build by using poles to support purlins, then the cost savings in that building is based on the poles being in the ground. You can add concrete later, or right away, but there is no advantage to putting posts on top of the concrete and installing purlins to the poss.

If you are going to pour concrete, then standard stick framing becomes about equal in cost for most buildings. If you plan on finishing off the walls with plywood or sheetrock, then stick building becomes significantly cheaper then pole building.

For me, the place where you decide how you want to build it is based on if you are pouring concrete first. If there is a concrete slab, stick building becomes the better choice.

The other choice is going with a metal clear span building, and then it gets more complicated on what is better based on the span and height of the ceiling required. But with both stick framing or metal, you have to have the concrete poured first.

 

[ovrszd]

That's your thinking. But you have never actually tried using a tracked skid steer for foundation pad construction, or you would not be saying that.

I'll go with Eddie on this. Any tracked vehicle is horrible for compaction.

A CTL is an excellent tool that most contractors have on hand. But they don't have it because it packs well.

 

[deezler]

^ I mean, the entire point of having tracks on a skid steer is to intentionally LOWER the ground pressure. Machines are made specifically to do compaction, why not use the right tool for the job when a rental is cheap. For me, a I bought a $500 used plate compactor with a trusty honda motor on it, and it's earned every penny. Sure, it takes a while to do multiple passes on a large building or patio footprint, but no big deal.

 

[deezler]

If you plan on finishing off the walls with plywood or sheetrock, then stick building becomes significantly cheaper then pole building.

For me, the place where you decide how you want to build it is based on if you are pouring concrete first. If there is a concrete slab, stick building becomes the better choice.

Good call on the interior sheetrock or plywood, I forgot about that advantage for stick framing also.

I would slightly modify your second statement, to say, "if there is a concrete foundation, stick building becomes the better choice". This distinction is important for anyone in a northern climate where we have to put a foundation below the frost line; we don't tend to do monolithic slabs up here that also support the building walls.

The slab inside the building is then the same price and difficulty regardless of wall construction method, more or less.

 

[ovrszd]

My shop and house are built by digging a footing with a trencher, below frost. Poured full of concrete. Poured slab resting on the poured footings. Stick built on top of the slab. My shop is 39x48, finished and heated. My house is 40x72, finished and heated. Been in them almost 3 years with no problems.

If a shop building is going to be finished and heated I believe it's best to be stick built. I only have use for a pole building if it's non finished, non heated and used for crude storage.

 

[Egon]

^ I mean, the entire point of having tracks on a skid steer is to intentionally LOWER the ground pressure. Machines are made specifically to do compaction, why not use the right tool for the job when a rental is cheap. For me, a I bought a $500 used plate compactor with a trusty honda motor on it, and it's earned every penny. Sure, it takes a while to do multiple passes on a large building or patio footprint, but no big deal.

Vibrating plate compactors on clay do not work well for a cohesive packed base!

 

[adlertom]

Ok I gotcha. Sure, you can anchor 6x6 posts atop a foundation and build a normal style pole barn that way. But I have to question why - you are making a hinge point where the posts anchor to the foundation. Just seems less sturdy. Whereas when you stick frame, which it sounds like we concur on, you have an entire 2x6 bottom plate repeatedly anchored into the foundation, and a much more sturdy box frame of a building constructed atop it.

Yes, 2x6 stick framing typically costs more than a pole building, but it's primarily because of the need for a full conventional foundation. You are doing that anyway, sounds like. I would price it out to see how much building your side walls out of standard 2x6 framing would cost, in comparison to buying expensive 6x6 poles that are now somewhat tricky to anchor to the foundation. You can still use the same roofing trusses atop a standard 2x6 framed wall. Only difference is, your building will be stronger, easier to insulate, wire, and so on.

But I would also still consider just making a big dirt pad that is somewhat larger than the building size, properly compacted in 6" lifts, and then just put your poles in the ground normally. I bet this would be cheapest overall.

The vertical posts (some builders use 6x6s, others use multiple 2x6 boards screwed together in a laminated fashion) are anchored to steel brackets set in the concrete foundation. So, the attachment method is quite secure.

True, I will already have a foundation, but stick framing on top of that would still cost more. More overall volume of wood is required, and the labor cost/time required to construct is higher.

I don't care for the idea of putting wooden poles directly into the ground. Yes, it would be cheaper and probably even last for a while, but they will eventually rot.

I do have a smaller 24x32 workshop/garage that is stick built, and I'm quite happy with that. However, almost anyone around here putting up a large-ish or tall-ish building without interior walls, such as a warehouse, garage, retail space, etc. uses either wood post-frame or steel beam construction.

 

[rademamj1]

Why does everyone believe tracked skid steers are useless for compaction. I thought the same way, and found that reality to be much different than what I thought. We have a new subdivision going up near my home, about 225 new homes under construction, all in the 2500 to 3800sq-foot range. These have Concrete foundations on typically a 24" thick compacted select fill base. Foundation crews are using a New Holland tracked skid steer (24" tracks) for distribution and compaction of the select fill base. It is done by layers, with 3" to 4" thick fill being spread and compacted until the full 24" thick pad is completed.

I went online and found three university academic studies done on this very subject.
The attached picture shows compaction data for both tracked and wheeled skid steers, and also varying the layer thickness of fill material. It shows tracked skid steers outperformed wheeled skid steers with normal tire psi tire inflation of 45psi. Wheeled skid steers only out performed tracks, if the tires were over inflated to 65psi. As expected, compaction was better achieved with thin mutiple layers. Rather than trying to compacted a very thick single layer of fill.

 

[4570Man]

Why does everyone believe tracked skid steers are useless for compaction. I thought the same way, and found that reality to be much different than what I thought. We have a new subdivision going up near my home, about 225 new homes under construction, all in the 2500 to 3800sq-foot range. These have Concrete foundations on typically a 24" thick compacted select fill base. Foundation crews are using a New Holland tracked skid steer (24" tracks) for distribution and compaction of the select fill base. It is done by layers, with 3" to 4" thick fill being spread and compacted until the full 24" thick pad is completed.

I went online and found three university academic studies done on this very subject.
The attached picture shows compaction data for both tracked and wheeled skid steers, and also varying the layer thickness of fill material. It shows tracked skid steers outperformed wheeled skid steers with normal tire psi tire inflation of 45psi. Wheeled skid steers only out performed tracks, if the tires were over inflated to 65psi. As expected, compaction was better achieved with thin mutiple layers. Rather than trying to compacted a very thick single layer of fill.

View attachment 724137

Because they’ve never tried doing it. Sure a vibratory roller is better but a tracked skid steer with a bucket of dirt will compact as good as a tractor or any other off road vehicle will do.

 

[LD1]

The vertical posts (some builders use 6x6s, others use multiple 2x6 boards screwed together in a laminated fashion) are anchored to steel brackets set in the concrete foundation. So, the attachment method is quite secure.

True, I will already have a foundation, but stick framing on top of that would still cost more. More overall volume of wood is required, and the labor cost/time required to construct is higher.

I don't care for the idea of putting wooden poles directly into the ground. Yes, it would be cheaper and probably even last for a while, but they will eventually rot.

I do have a smaller 24x32 workshop/garage that is stick built, and I'm quite happy with that. However, almost anyone around here putting up a large-ish or tall-ish building without interior walls, such as a warehouse, garage, retail space, etc. uses either wood post-frame or steel beam construction.

Are you finishing the inside of the building? If so...it's actually less wood to stick build it.

And what is the truss spacing? I'd you plan 2' or 4' oc trusses and set posts now you have the extra expense of a header out of 2x10 or 2x12's. Stick built wall....no header needed.

You do add the cost of some sheeting on the outside.

 

[ovrszd]

Are you finishing the inside of the building? If so...it's actually less wood to stick build it.

And what is the truss spacing? I'd you plan 2' or 4' oc trusses and set posts now you have the extra expense of a header out of 2x10 or 2x12's. Stick built wall....no header needed.

You do add the cost of some sheeting on the outside.

My shop uses 4ft trusses, finished inside, stick built. My builders assured me it was cheaper to do so.

 

[LD1]

My shop uses 4ft trusses, finished inside, stick built. My builders assured me it was cheaper to do so.

There are literally dozens of ways to build a shop/garage/barn. And I wouldnt say any one way is better than the next. And cost all comes down to the cost of the building materials AT THE TIME of purchase.

There are SO many variables....and they are all interconnected. Change ONE variable....and it changes ALOT.

Stickbuilt requires a foundation or a monolithic pour. That adds cost and so does sheeting before the metal goes on. But you save the expense of treated posts and post holes.

Another variable is 4' vs 8' OC trusses. IF you are building a barn that is 64' long, that will take 17 trusses at 4' OC. Those trusses are likely gonna be ~$150ea for a 32' or so span. Thats almost $5000 in trusses, then you need a double 2x12 header. And 2x12 lumber aint cheap.

Jump that to 8' trusses and set them right on the posts. Only need half as many trusses (9)....and they are more expensive but not double. Like maybe $225ea. So only about $2000 in trusses. You also dont need the 2x12's for headers. But now you add complexity for the purlins standing on edge. Either hangers....or blocking....or long spikes driven by hand which adds significant time and labor (cost to build). Then there are 10' or 12' OC posts and trusses. Cheaper yet for just the trusses, but now 2x6 purlins on edge and definitely need hangers...so there is that added cost.

For walls, you can use 2x4 girts nailed on the outside of the posts and the building goes up quick. But then you have to do the same thing on the inside if you plan on finishing. Another option is 2x6's laid flat between posts (like a stud wall only horizonntal). Takes more time to frame up the initial shell, but that pays dividends in the long run because you are already ready to finish the interior. And actually, a single 2x6 is cheaper than TWO 2x4's (one inside and one outside).

Again, dozens of ways to build. None are really better than the next. Because there is always a tradeoff.

But dozens of buildings I have designed and laid out either for myself or for friends/family....cost was never really a factor. Because on a building with $30k of material (finished and concreted)....the difference between posts vs monolithic vs footer/block wall, and 4', 8', 12' OC trusses is rarely more than a few hundred bucks at the end of the day.

In reality, the decision on "how" to build has came down to Labor, equipment, and time at hand. Trying to get a shell of a building up before winter sets in it might be best to bang the wall girts up on the outside and deal with the inside later vs 2x6's horizontal between posts. Or not having the skill or time to lay block or equipment to dig footer so setting posts might be the best.

When I built my 40x72 shop....I had a backhoe and a post hole digger. The price of the block and concrete for a footer (I know how to lay block and have backhoe to dig footer) was darn near identical to the cost of treated posts and a header all the way around the building. IT took more labor to build my building, but didnt cost any more money to lay a 6-course block foundation and then build the walls in 16' long sections and sit upon the wall.

Like I said, lots of ways to build and I wouldnt call any of them "wrong" ways. BUT, using posts AND a monolithic pour dont make sense to me. only thing I see it saving is the sheeting because you can now put horizontal girts for the metal....and maybe that makes sense with current prices. Gotta adapt to the lumber market I guess

 

[deezler]

The vertical posts (some builders use 6x6s, others use multiple 2x6 boards screwed together in a laminated fashion) are anchored to steel brackets set in the concrete foundation. So, the attachment method is quite secure.

True, I will already have a foundation, but stick framing on top of that would still cost more. More overall volume of wood is required, and the labor cost/time required to construct is higher.

I don't care for the idea of putting wooden poles directly into the ground. Yes, it would be cheaper and probably even last for a while, but they will eventually rot.

I do have a smaller 24x32 workshop/garage that is stick built, and I'm quite happy with that. However, almost anyone around here putting up a large-ish or tall-ish building without interior walls, such as a warehouse, garage, retail space, etc. uses either wood post-frame or steel beam construction.

Sounds like you are pretty set on your plan. Which, I am sure, will result in an excellent and robust structure! Good luck moving forward and remember to share lots of pics here.

So are you sure you will never finish the interior of the building? Storage only?

 

[rademamj1]

There are literally dozens of ways to build a shop/garage/barn. And I wouldnt say any one way is better than the next. And cost all comes down to the cost of the building materials AT THE TIME of purchase.

There are SO many variables....and they are all interconnected. Change ONE variable....and it changes ALOT.

Stickbuilt requires a foundation or a monolithic pour. That adds cost and so does sheeting before the metal goes on. But you save the expense of treated posts and post holes.

Another variable is 4' vs 8' OC trusses. IF you are building a barn that is 64' long, that will take 17 trusses at 4' OC. Those trusses are likely gonna be ~$150ea for a 32' or so span. Thats almost $5000 in trusses, then you need a double 2x12 header. And 2x12 lumber aint cheap.

Jump that to 8' trusses and set them right on the posts. Only need half as many trusses (9)....and they are more expensive but not double. Like maybe $225ea. So only about $2000 in trusses. You also dont need the 2x12's for headers. But now you add complexity for the purlins standing on edge. Either hangers....or blocking....or long spikes driven by hand which adds significant time and labor (cost to build). Then there are 10' or 12' OC posts and trusses. Cheaper yet for just the trusses, but now 2x6 purlins on edge and definitely need hangers...so there is that added cost.

For walls, you can use 2x4 girts nailed on the outside of the posts and the building goes up quick. But then you have to do the same thing on the inside if you plan on finishing. Another option is 2x6's laid flat between posts (like a stud wall only horizonntal). Takes more time to frame up the initial shell, but that pays dividends in the long run because you are already ready to finish the interior. And actually, a single 2x6 is cheaper than TWO 2x4's (one inside and one outside).

Again, dozens of ways to build. None are really better than the next. Because there is always a tradeoff.

But dozens of buildings I have designed and laid out either for myself or for friends/family....cost was never really a factor. Because on a building with $30k of material (finished and concreted)....the difference between posts vs monolithic vs footer/block wall, and 4', 8', 12' OC trusses is rarely more than a few hundred bucks at the end of the day.

In reality, the decision on "how" to build has came down to Labor, equipment, and time at hand. Trying to get a shell of a building up before winter sets in it might be best to bang the wall girts up on the outside and deal with the inside later vs 2x6's horizontal between posts. Or not having the skill or time to lay block or equipment to dig footer so setting posts might be the best.

When I built my 40x72 shop....I had a backhoe and a post hole digger. The price of the block and concrete for a footer (I know how to lay block and have backhoe to dig footer) was darn near identical to the cost of treated posts and a header all the way around the building. IT took more labor to build my building, but didnt cost any more money to lay a 6-course block foundation and then build the walls in 16' long sections and sit upon the wall.

Like I said, lots of ways to build and I wouldnt call any of them "wrong" ways. BUT, using posts AND a monolithic pour dont make sense to me. only thing I see it saving is the sheeting because you can now put horizontal girts for the metal....and maybe that makes sense with current prices. Gotta adapt to the lumber market I guess

Sounds like you are pretty set on your plan. Which, I am sure, will result in an excellent and robust structure! Good luck moving forward and remember to share lots of pics here.

So are you sure you will never finish the interior of the building? Storage only?

The vertical posts (some builders use 6x6s, others use multiple 2x6 boards screwed together in a laminated fashion) are anchored to steel brackets set in the concrete foundation. So, the attachment method is quite secure.

That's the method Morton Building uses for their structures. All wall column supports are three boards of 2x6 bolted to pre-drilled steel brackets, which are anchored by bolts embedded into the foundation just at the very end of the concrete pour. They are typically using 1/2" x 8" bolts, embedded leaving 2" of the bolt threads exposed. Two bolts per bracket. So 30 wall columns require 60 bolts anchored into the concrete, taking about 10mins to position all 60 bolts. Then the slab is powered trowled and finished.

Approximately, 30 days later you come back and place the brackets into position using a washer and double nuts per bolt. Be advised, some bolts do misalign during the curing, so a few brackets may require slight re-drill of the holes.

Morton building claims this process allows them to warranty buildings to 120mph winds. Morton found that using mutiple 2x6's are 20% stronger than a single 6x6's for the wall columns. At no point are these wall columns in contact with the soil or concrete. They are in contact with a predrilled and painted steel bracket. Let me post a picture of these columns and brackets from an actual Morton building. I will do that picture post tomorrow.

 

[LD1]

That's the method Morton Building uses for their structures. All wall column supports are three boards of 2x6 bolted to pre-drilled steel brackets, which are anchored by bolts embedded into the foundation just at the very end of the concrete pour. They are typically using 1/2" x 8" bolts, embedded leaving 2" of the bolt threads exposed. Two bolts per bracket. So 30 wall columns require 60 bolts anchored into the concrete, taking about 10mins to position all 60 bolts. Then the slab is powered trowled and finished.

Approximately, 30 days later you come back and place the brackets into position using a washer and double nuts per bolt. Be advised, some bolts do misalign during the curing, so a few brackets may require slight re-drill of the holes.

Morton building claims this process allows them to warranty buildings to 120mph winds. Morton found that using mutiple 2x6's are 20% stronger than a single 6x6's for the wall columns. At no point are these wall columns in contact with the soil or concrete. They are in contact with a predrilled and painted steel bracket. Let me post a picture of these columns and brackets from an actual Morton building. I will do that picture post tomorrow.

Morton doesn't (or didn't) always do that.

Laminated 2x6 posts....sure. that was always a staple of their building.

But I can show you DOZENS of their buildings built in the last 3 decades with those posts imbedded in the dirt

 

[rademamj1]

Todate, I have not seen a Morton Building without a concrete foundation. But I must admit, I have only looked at less than 15 Morton buildings in my area of Texas. The attached pictures show how they mount the wall columns onto the concrete foundation.

View attachment 724375View attachment 724376

 

[LouNY]

Many Morton buildings do not get a poured floor, dirt, gravel or whatever is cheap.
They will have the poles (sandwiched 2 x 6 or 8's) set in the ground.

 

[Rustyiron]

Back to compaction,
I've never seen a roller on tracks.

 

[rademamj1]

Back to compaction,
I've never seen a roller on tracks.

We use them all the time whenever clients make the request. A Vibratory roller mounted on tracked Skid Steers is Awesome.