Pole Barn Post Longevity

[bebster]

I'm planning to construct a storage shed or pole barn for my tractor. Typical frost line in this part of the country is 4' per code, so most construction has a poured concrete foundation with footers 4' below grade.

Seems overkill for an unheated shed, so the pole barn approach has appeal. But I'm concerned that the poles inserted into the ground (whether in concrete or gravel) will have a limited life. I'd like this shed to last decades and not have its main supporting poles rot at the base.

Any idea what life to expect, and what the best technique would be for putting in the poles?

Once the poles are in, it makes sense to put in a concrete slab floor, so that tractor attachments can be dropped there on a dry level surface. But what approach is best to use to seal off the area near the ground between the poles? Thanks for any suggestions.

 

[Slamfire]

The absolute best would be locust posts. I've seen some that have lasted 70 years. May or may not be possible were you are. The next choice would be the posts used for utility meter mounting on mobil home sites, or used utility poles. I've seen some of them last 40 years.

 

[lamarbur]

A lot of guys are now pouring concrete base and when hard, placing a spacer on concrete, then the poles. Seems to work out well by not having the posts actually in the concrete pour, but placed above that..

 

[bebster]

Posts on spacers are typical in deck construction. Only problem I see is with hurricanes. With a roof up 10' or so, the windage might overpower the spacers tying the wood posts to the concrete. A possible solution, but seems to be not ideal unless I'm missing something.

 

[lamarbur]

they do this where I live pretty mcuh standard now, I'm in the hills of Union CT at 1050 ft above sea level and we get horrendous winds here and obviously a lot of snow, so it has to work, at least here it is,

 

[EddieWalker]

In my area of Texas we get over 60 inches of rain a year. I had a barn on my land from before WWII.

It was 40 feet by 120 feet long. The roof had caved in, probably from the branch sticking through it.

I knocked it down a couple months ago with the backhoe. Only a couple of the posts were rotted, the others are still sound. They were 6X8's about 16' feet above ground and around 4' in ground. No cement. Looked like pine with a dark tar like stain on them.

I'm guessing around 70 years it lasted. I've met some of the WWII vets who trained on my land who remember it then.

Good Luck,
Eddie

 

[Slamfire]

That was propably the heavy creosote that they used to use on utility poles and pilings, can't get that any more.

 

[Dave___in___CT]

Hi...

Pressure treated posts work... .40cca for ground contact...
Use native soil for backfill... a few inches of concrete at the bottom of the hole provides a bigger footprint for the post...


Dave...

 

[Steven]

They make metal brackets that you can set in the concrete of the footings and attach the wooden poles to this stops the ground contact and rotting of post. not sure who made them but have seen them at home depot. I used a smaller version of this on my deck to secure 4x4's to concrete so they where not just resting on top.

check out this site pole barn building

 

[BIGBLUETOY]

I'm in the planning stages of building a 36x40 pole style garage. I have been looking at pre-cast concrete post (columns). Check out www.permacolumns.com.
I have sent them email earlier today for prices on their product.
Scott

 

[bebster]

Scott,
The link didn't seem to work. Seems like you might be on to something. Can you please repost it? Thanks.

 

[slowzuki]

My sisters pole barn is about 25 years old built with untreated posts in topsoil/poorly drained soil. The spruce poles have about 3/4" of rot on them where the manure from the sheep that occupied the barn was piled.

Our back deck posts was pulled up at 20 years old, pressure treated posts. They were in wet sand all their life, I pulled them up in August and they were sopping wet but looked brand new!

Our front deck posts is pentoxed/creosoted hemlock and is now 25 years old with no signs of rot. The untreated decking lasted 20 years before it rotted out.

Ken

 

[BIGBLUETOY]

The correct address should be www.permacolumn.com
Sorry I had an extra s and a period at the end in my
previous reply.
Scott

 

[BIGBLUETOY]

The general manager from Perma Columns emailed me and the PC6400 sells for 57.35 ea picked up at Craigville, IN. Sounds like they will not arrange any trucking, he said that I would have to pick them up at their site, I live in upstate NY so that won't work. In my original email I asked him how much each one weighs but he did not give me that info so I emailed him back.
I will probably go with the 6x6 PT posts poked in the ground for my garage.

 

[bebster]

Looks to me like the Perma columns are the equivalent of poured concrete sonatubes below grade with the wooden posts attached to them above. They have a beefier tie-down bracket.

This technique makes a lot of sense, and will clearly last a long time, since there is no wood in contact with the ground (pressure treated or not).

Very similar to how decks are built in the north. Only a pole barn is an enclosed deck with a roof. I guess the tie-down needs to be adequate for the increased windage, and that's my only concern. So I looked at Simpson Strong-Tie components, and found some tie-downs that seem to do the job. Galvanized Post Bases

 

[dmccarty]

bebster,

I'm putting my 6x6 PT column on concrete piers. I'll use
Simpson Strong tie post bases to connect the 6x6 column to the
pier. It just seems better than putting the wood in the
ground.....

I have not gotten prices yet but I'm pretty sure that I'm going
to go with common wood trusses. They can span my 24 foot
width with ease so that I don't have to internal columns.

At least that is todays plan.

Later,
Dan

 

[Junkman]

Dan....... you are going to find that the Simpson Strong Ties are just a shade too small for the PT 6x6.. about a saw kerf on two adjoining sides will do it. I set mine by drilling a hole in the center of the pier after I had everything aligned and set a piece of threaded rod into the hole after pouring in some of the high strength fast setting cement. Tightened them down with a 1/2" ratchet and couldn't pull the threaded rod out, so I know that they are going to stay put.....

 

[bebster]

Dan,
What's the diameter of your piers? In NC you probably only have a 12" frost line, so I'm sure they don't have to be that deep. But I assume you'll want them wide enough to support the load on the post. With no interior posts, that's probably a decent load.

 

[dmccarty]

Bebster,

I'm thinking of putting in 12 inch diameters with a footer that is at least 28" square and 12 inches thick.

Why?

Well, 12 inches gives me some play to make sure the piers are
all inline and square.

I read somewhere that the footer should have 8" on each side
of the pier. I think that is overkill but what the heck.

The frost line in my area is supposed to be 6 inches.

I'm planning on digging about 24-32 inches deep. The pier
tubes are 4 feet so I'll cut them in half to get 2 feet. I want at
least 8 inches of the pier above grade. So I should be digging
a 28 inch deep hole.

Per an earlier TBN conversation I'm going to backfill with ABC.

I'll talk to the building inspector to see what he says. I'm still
waiting on info from the truss company. If I did my math
correctly, a big if sometimes, the loads really are not that bad
for the roof. Eventually one side of the barn will be a shop
that will be guilt on beams attached to the posts. That
requirement has made the loads a bit interesting on that side
of the barn...

Later,
Dan

 

[dmccarty]

Junkman,

Thanks for the tips.

Later,
Dan