books on building pole barns

[Spencer]

<blockquote><font size=1>In reply to:</font><hr>

I gather that a lot of professional builders simply drop in a concrete "cookie" and plunk in the pole. And a lot of self-builders concrete them in to ground level, thinking they need the strength. The latter makes me wonder how long their poles will last being trapped in concrete all its life. I've seen what that does to wood.

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Jim, can you or others please follow up on this. I have read previous threads on TBN saying that treated posts and concrete don't mix. I just received my building permit for my pole barn and plan on starting the project as soon as my wife finishes up her current two projects. I asked both our local building inspectors about the reaction between treated posts and concrete and they both laughed at the idea that the concrete might damage the posts. I will be required to place conrete cookies (at least 14" x 4") in the bottom of the holes for the posts to sit on. I am then required to pour concrete around the posts but it has not been made clear to me exactly how high I must go. My water table is quite high here and unless I get convincing evidence on why I shouldn't cover the posts in concrete I personally believe that I will be better off with concrete againts the posts instead of water.

 

[WVBill]

"<font color=blue>How does your definition of friction piles equate to the concrete collars idea?</font color=blue>

From what I remember of my research when building my pole barn: The Friction force is proportional to the amount of surface area of the pole in contact with the earth. The concrete collar in effect becomes part of the pole and increases the surface area of the "pole" in contact with the earth, thus increasing the friction force. The top and bottom surfaces of the collar have significantly less effect on friction force (and weight bearing capacity) than the cylindrical side surfaces.

 

[jimgerken]

I will tell you what I understand, and hopefully others can follow with evidence. It is not a problem with the concrete itself in contact with the pressure treated pole, it is the moisture that will be trapped inside the concrete. Any wood will last much longer if kept dry. By casting a concrete "cup" around the pole, water will go in and never drain out. So the pole just sets in it till it rots off, probably at ground level, in my experience. Drainage is the key. On my 3 pole buildings, I backfilled with crushed rock (above the concrete collar) for good drainage.
So here's the whole plan: Drill/dig holes, measure depth to ensure below frost, toss in one spade of crushed rock and pack it into the bottom of the hole with a 4" by 7 or 8 foot fence post, drive (maybe pre-drill) landscape spikes into each side of the pole, 8 inches from bottom leaving 3" sticking out and bend them up a little to make the whole thing smaller to fit the 12 inch hole, drop pole into hole, position and brace on two sides, mix some concrete enough to fill hole 1 foot deep around pole, let stand and harden, resist temptation to backfill hole full as long as possible in case you wish to tip poles to line them up better when you girt the walls, when you finally do backfill use crushed rock (3/4" minus), and tamp it in. Get at least one girt on up high before you settle on the poles' positions and backfill. Here's a pic of me and my S10 "dumptruck" backfilling a pole hole with crushed rock from the driveway.

 

[jimgerken]

Cool, thanks.

 

[gmason]

A neighbor of mine is putting in a deck right now and I saw him dipping his 6x6 posts into a bucket of tar like liquid. Similiar to the stuff they spray on the outside subgrade walls of a house before backfilling to waterproof.

I was at the beach last weekend and saw several water's edge properties that were using preasure treated, but it also looked like that they had painted on even more of the green preservitive than it came with. Is there some special marine grade preasure treating process for wood?? For use in lakes and oceans?
I would figure if a pileing could survive in the ocean for 25 years, it could take an occasional watering in my soil.

gary

 

[WVBill]

Jim: I understand and agree with the problem of the concrete "cup" and water. I went ahead anyway with this thought in mind: 1) I put a form around the pole so that the concrete cup actually ended up about 4" above grade so that no water would run in between the pole and concrete. 2) The poles actually end up inside the structure after the girts and siding are put on so they are not exposed to any rain hitting them and running down the poles into the cup.

I see you have a LoadHandler too. Man what a work saver! I was skeptical at first but it has "handled" as much load as my truck will take in everything from mulch to gravel to pallets of stone.

 

[jimgerken]

Yes, the Loadhandler is a great tool. I bought it just for this project. I found it a local Checker auto on closeout for 26 bucks! After using it, I was tempted to go back and buy the other one. Here I am loading the dumptruck...

 

[rationalizer]

Mosey,

I found "Building a Multi-Use Barn" by John Wagner very helpful. The book focuses on a generic 24x30 barn - but it gives you lots of options/ideas. Are you set on a "pole barn"? I ended up putting in a true foundation - I know I'll never have to worry about the underground structure rotting. If you will be pouring a concrete floor anyway it might not be that much more...

 

[yooperdave]

There seems to be quite a bit of concern on this list regarding deterioration of the wood poles.

There are different levels of pressure treatment depending upon the application. Wood in direct contact with the earth should have a preservative retention of 0.60 pcf - sometimes called out as "brown treated lumber".

Lumber used for decks or not in direct contact with the earth is usually treated for a retention of 0.40 pcf - sometimes called out as "green treated lumber". As you would guess, green treated costs less than brown treated.

The warranty period for brown treated poles regarding rot from the various building manufactures is around 40 years.

This should not be a problem.

Yooper Dave

 

[Soundguy]

Yep. The larger the pile, the more surface area, the more friction. Add to that if the concrete is only at the bottom, with earth covering it, there is also the added force of displacing that dirt to pull the pile out.. kinda like a toggle bolt idea.

If the concrete area is well attatched to the pile, via nails or skikes protruding from the pile.. It would only help, and not hurt any.

As far as load bearing capacity is concerned, keep in mind that the maximum load carried will be equal to the weakest area of the pile. That in mind, if you are in a loose soil, or a wet soil, having a large base ( via a concrete sleave or footer block )will help distribute the caried load, and again, can only be a benefit.

Soundguy

<font color=blue>From what I remember of my research when building my pole barn: The Friction force is proportional to the amount of surface area of the pole in contact with the earth. The concrete collar in effect becomes part of the pole and increases the surface area of the "pole" in contact with the earth, thus increasing the friction force. The top and bottom surfaces of the collar have significantly less effect on friction force (and weight bearing capacity) than the cylindrical side surfaces.