minimum pad thickness

[Jared Drake]

Just because sometimes I think a lot, let's say I were going to cut down some oak trees and use them to build a pole barn that would eventually be used as a cabin. If I were to float a pad, how thick would it need to be? Is four inches enough? What're the biggest poles a person can buy at Home Depot or Lowe's? How big around and how long, I mean? This may be a quick way to get my "Plan B" cabin started, since I can't build a little at a time (the wood would be damaged by weather). Also, can pole barns be two-story?
Jared

[glenn kangiser]

Most slab on grade house pads are nominal 4" that I have seen - many times they are 2x4 thickness or about 3.5".  This floor is strong enough even for tractors etc. if the ground is solid underneath.

[PEG688]

[size=12]   4" is the norm as Glenn said . We thicken ours at garage doors and also any where you will have bearing , IE exterior walls , posts / walls that would be point loads , etc.  

 So if it's pole barn and it won't be driven into , as in parking a car / truck / tractor etc 4" would be ok.

 These oak trees you'll be cutting , will they become your pole barn post? Buried into the ground 3' to 4' ?

 If so they should be PT posts, red oak will rot if it's touching the gnd.   White oak won't do much better buried either.

 Pole barns can be designed as  1 1/2  stories , generally more like mezzaninies, not sure if I've seen a true 2 story PB.  It would take a pretty large post I would think [/size]

[glenn kangiser]

Many times around here pole barns are made 16 feet or more tall to get a hay squeeze machine in there - seems they need 20'.  Upper floors would stiffen the structure.  Ken Kern mentioned pole building as being a great way to make a house.

[John Raabe]

I'm afraid I have to respectfully disagree with Ken. When I was working with Ken Kern we designed a number of pole buildings. Many were turned into living space. Ken was great at broad stoke ideas and did great pen and ink sketches of things that sometimes couldn't be done in reality. He tended to be light on the details....  :-/

Pole frame buildings is one area we had problems (and remember, this was the early 1970's when oil was cheap and codes were very easy).

One of the main problems of a pole structure is what to do when you want to insulate. Where does it go? Inside or outside the poles? How do you make the connections? How do you seal this against air and water? How does it settle?

In most cases when you get a design worked out that can be sealed and insulated to current code you have done it with 2x6 framing and can therefore hold up the building with that! It becomes more cost effective (at the design phase) to throw away the poles and build with standard stud framing.  

For a barn, shop or garage a pole building makes sense. But not for a full time residence in anything but an Hawaii like mild climate where you don't have to insulate or seal against drafts.

Do a PT wood stud perimeter or post and beam foundation if you want to stay away from concrete.

[glenn kangiser]

Nice to have someone here who knows firsthand.

[glenn kangiser]

I also have to admit that I can think of some pole barns with uneven eave lines due to sinking of some of the poles.

[PEG688]

I also have to admit that I can think of some pole barns with uneven eave lines due to sinking of some of the poles.

 [size=12] Could be rotten poles as well , Eh Glenn [/size]

[manhattan42]

Agree with John.

For pad thickness remember also that a 3.5" pad is NEVER thick enough the bear the weight of concentrated loads from columns or bearing walls.

Even slab foundations require footings to be a normal minimum depth of at least 12- 24" thick around the perimeter and under weight bearing interior columns or deeper depending upon the frost depth for the region.

Though the slab itself may only be 3.5" nominal, the footings rarely, if ever,  are.

[glenn kangiser]

A rotten pole is a possibility PEG.  Many were put up around here with treated poles and look the same as any all steel barn from the outside.  Most of them still look good.  The sagging one has probably been that way for 30 years.  I told some people today that if my RV garage lasted 30 years I probably wouldn't have to worry about it anyway.

[Jared Drake]

Some reasons I'm considering a pole barn: I'll have very little money at any one time to do work with. I can get the exterior up w/out having to pour a pad and or footings, so I can come back later and dig water lines and septic lines. Then, if I never get that far, I'll still be able to pour a thin pad and at least have a storage building at my dad's farm. I can get some barn tin together and once I get up my lath and purlins I can enclose it and keep the wood supports from rotting. Right now I'm looking at www.socketsystems.com for parts.
As far as insulation goes, it wouldn't be any different than building a metal building. Except that in between the 6" or 8" square poles, I'd have a stud frame, maybe on 24" centers. Then I could use tongue and groove lumber for wall covering or sheetrock, whichever. Remember, this is just for occasional use and to satisfy my urge to build something. (Plus, the paranoid side of me says I can use it if something goes wrong with America and we have to leave the city and sustain ourselves.)
I love this forum. I like being able to explore all these possibilities that I've looked at so far w/out spending a dime. When I build, I know it'll be right for what I want.
Jared

[John Raabe]

Square poles make things a lot easier! When I was working on pole buidings we always used round - typically telephone poles that went from embedded in the ground to the roof peak. For a two story house they were pretty long and tapered.

That's where my head was at (to use a 70's term).  

If you can get straight 6x6 PT posts long enough for roof support you will have a much easier time since you can frame and insulate between the posts.

[keyholefarmhouse]

I have a pole barn on our property.  I have and still do look at it and wonder how to do something with it.

It's great for what it is.  Storing equipment out of the weather and locking it up when your finished.

I'm thinking again about putting a small finished area for tools and heat.

Basicly it will be building a building inside a building.

Let pole barns be pole barns.