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.