Pole building life with concreted poles and floor?

I found some threads here pertaining to pole life that were not too impressive but seemed 90% of people do not concrete their poles in and the ones that did, seemed to have good life. I also did not see much mention of a concrete floor or drainage that would keep water away from the pole sites.


I am curious to hear from anyone that HAS had good long life so we can determine WHY. Rot is typically a function of moisture and even steel buried in the ground would fail if subjected to constant moisture.

I am just not sure right now whether concrete or gravel is the right choice. I certainly would not backfill with dirt since gravel and sand would be far superior for drainage. I am trying to design for a method of replacement in any event but also trying to design a building that will stay solid for 100yrs. Steel I-beam is not an option.

I think the material is big factor pine poles VS pressure treat, then keeping them dry, my brother just pulled some ceder poles that had been used for erosion over 100 years the part in the water/ground looked like the day they where installed never had oxygen to them.

Saw these being used in ~60' lengths on local utility upgrade. Wonder if smaller scale version would be useful in ag building applications, ie: pole barns?
With direct burial, they would seem to eliminate the drainage/rotting problems.
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for a timber pole to rot it needs moisture and oxygen. For bridge abutments I have designed that needed piling if they are always under water then always used untreated piling.
For timber bulkheads and walls exposed to oxygen we used creosote-18#/cf or CCA-1.0# cf.
All the research I have done on timber posts into soil suggests that the concrete should never encapsulate the bottom of the post for better life.
so concrete around the post but not sealing the bottom---or no concrete around the posts--but it may be set on a hardened concrete footing.
I my self have built sheds and decks on treated posts with gravel around and under the post to facilitate drainage

Fastline.. Have SEVERAL pole barn type structures here on the farm that are dating back to the early 60s . Well over 50 years old. My dads way was dig a 12 to 14 in hole. Have several that the pole was set with half bag of quick-creet in the bottom of the hold dry then some rock and finished off with the rest of the bag at the top. Also have some that used 8X8 pressure treated set in wet concrete with concrete floors. Have not had any building or pole failure and no sign of rot at this time. Here folks on hear all time saying not to use concrete. Here is we go to sit a corner fence post, mail box, or light pole,for what ever the quick creet is the way to do it.

Hey there.

I don't know about a hundred years but I have installed (and dug up) Scores of pressure treated sign posts which went 20+ years with no evident rot.

The procedure is:

Auger hole at least double the size of the post.

Put a few shovels of pea gravel in the hole.

Set pole and brace two sides.

fill hole with dry concrete mix and wet the top with a bit of water.

The concrete mix will draw moisture out of the ground and the pole itself and will be steady after one day and solid after two. the pea gravel will prevent moisture from collecting around the pole.

This has worked for me and I hope it helps.

Brad

I have to add my comments to this.
I have built many many wood decks.

I have done decks many different ways.

But the best way to put in wood posts is
to dig down 48" twice the diameter of the post.
Then put in a 6" thick concrete pad on the bottom of the hole. Then set the post on the crete pad.
Then fill with pea gravel and sand mixture. Use braces to hold post plumb.

Here"s the amount of preservative you should check for, depending on the type of chemical. These are the amounts the manufacturer"s are required to pressure in, for structure-critical foundations and building poles;
“NatureWood”
Alkaline Copper Quaternary ACQ 0.60 pcf for Ground Contact / Critical Structures / Foundation Use

“Micro-Pro / Smart-Sense”
Micronized Copper Quaternary MCQ 0.60 pcf for Ground Contact / Critical Structures / Foundation Use

“Micro-Pro / Life-Wood”
Micronized Copper (tebuconazole) Azole MCA 0.23 pcf for Ground Contact / Critical Structural / Foundation Use

Ordinary pressure treated lumber at the lumber yard will normally not have this amount of preservative. I"ve stuck many treated lumber projects in the groumnd, and after 15 years I can see the termites and thr rot. Would never want to see that in my pole barn

around here they are using concrete posts to come above ground then regular wood on up, but the concrete posts are about 90.00 each, i had to replace some of mine that lasted 16 yrs on my porch and i bought some of the PVC sleeves that slide over the 4x4 posts and put them in the ground then filled them with sacrete and put the post on top of that.

I just put up a little shed with 6x6 treated post. Where in fine sandy loam with good drainage. I augered a hole about twice the width down to 5 foot and added about 4 inches of crushed rock for a base. We held em straight and just added crushed rock and tamped the heck out of it as we back filled. Added a few spikes in the base of the poles for good measure.

I'll check back with you in about 20 years and let you know if it held up.

We built a pole tobacco barn with 6 x 6 treated poles in 1977 that is still standing straight today. We backfilled with gravel and out of curiosity I dug around 6 this summer and to my surprise they show no decay. I live in a humid climate that gets several inches of rainfall each year.

I've had a pole shop for over 20 years, hasnt fell over yet. If you use treated wood and do your proper landscaping you should not have a problem

With gravel backfill your post will be loose,and
act as sump for water in the ground.Don't know how you could call it superior for drainage.

Nothing wrong with compacted gravel or clay

I put several coats of tar on my posts before I plant them. I heat a bucket of tar and lower the posts into the bucket with the crane in the barn. Ellis

I put my 40 x 63 pole barn on a foundation. My thinking was that the old barns have been around for over 100 yrs on brick foundations.

The power company is putting in a new line and all of the poles are back fill with 1 1/4 rock.

Posts which have been properly treated for ground contact should never rot under any conditions. But of course you are dependent on your lumberyard and its supplier to provide you with good posts.

That said, there is a "right" way to set posts, and that is NOT to pour concrete around them. You need to first dig a hole that is about a foot deeper than how deep you want to set the post. (In most parts of the country, posts are set at 42 inches, so that means you need to go down about five and a half feet.) The hole needs to be at least ten inches in diameter near the bottom. You then pour a concrete plug to raise the bottom up to the depth you'll set the posts. This plug ensures that the posts will support the weight of the building without sinking. Once the plug has set up, you set the post directly on the plug. (Some folks place an asphalt shingle between the plug and post, the idea being that the shingle will seal the post's end grain under the weight of the building; I suppose it can't hurt.) You then backfill the first foot of the post hole with pea gravel. In theory the gravel allows water to drain away from the post. You then finish backfilling with dirt, although I like to throw half a bag of dry Quickcrete over the pea gravel to lock in the post.

The power company just yanked some pressure
treated poles from my property that were installed
in 1937. They are still pretty sound. I reused
them to build a bridge over a swamp.

It's all about the proper treatment.

As to how you install is up to use. Sinking poles
into a tight hole preserves the original purpose
of pole building. That is - they are somewhat
self-supportive vertically. When put into loose
holes and filled - they lose some of that
integrity unless the holes are filled with coarse
gravel or concrete. That may or may not matter to
you. If the poles are not tight in the ground -
then good braces and collar ties are needed.
Since so many people use trusses now-adays,
having good collar-ties is not an issue. A
peaked roof with no trusses or collar-ties pushes
the tops of the poles away from each other.

When you hear horror stories about poles rotting
fast - it's due to poles with poor treatment.
Here in NY - NO 4" poles are available with the
proper treatment. 6" poles are IF bought over 12
feet long. I needed some 8 footers recently and
had to buy 16 footers and cut them in half. Home
Depot and Lowes had 8 footers but with the light
treatment and not suitable for long-term burial.

Same goes for plywood. No lumberyard in my area
carries treated plywood suitable for burial.
Treated yes -but just a light ACQ or copper azole
treatment. I had to special order the "foundation
grade" 3/4" CA-C plywood I needed for long-term
in-ground use.

The type of wood plays a factor too. When dad built the hay shed back in the mid-60's he couldn't get all of the same poles. Half were one type of wood, maybe fir, and the other half were another type of wood. He wanted all of them to be the kind that didn't rot off as fast but I don't remember which one it was. When I tore the shed down ten years ago half the poles were rotted off and half were good as new. All of them were creosoted. Jim

The type of wood plays a factor too. When dad built the hay shed back in the mid-60's he couldn't get all of the same poles. Half were one type of wood, maybe fir, and the other half were another type of wood. He wanted all of them to be the kind that didn't rot off as fast but I don't remember which one it was. When I tore the shed down ten years ago half the poles were rotted off and half were good as new. All of them were creosoted. Jim

If you're talking about treated poles -a wood with a
fairly straight grain is needed so the chemical
treatment can be forced all the way through it.
That's why southern yellow pine is the most commonly
used wood for treatment.

If not pressure treated and just coated on the
outside - then you'd want a wood with natural
resistance. White Oak, Tamarack, Cedar, etc.