Barn Post Question

[jesnic]

Imagine the letter "I" in the ground with concrete around the bottom (footer)and small diameter concrete in the middle (and then larger again at the top. If you drill holes through the lower portion of the timber and run rebar through it, it will attach to the concrete and never be able to be lifted from the hole without pulling the ground around it. Around here, when inspections are required, the inspector wants to see a large diameter hole approx. 18" in diameter and 36" deep with a taper in the bottom. The bottom needs to be undisturbed soil and gravel set in the bottom for the post to sit on. I mix a little crete with the gravel, set the post, then pour crete around it. Another method is to drive galvanized pyles to bed rock and build on the flanges on top of the pyles. At a cost of about $500 per pyle, every 7 feet, it isn't cheap, but it lasts forever. Each pyle is rated to hold 20K lbs.

 

[Duffster]

Concrete cookies and gravel, then crete it in. Or you could use sona tubes over deck blocks and make sure to cut the sona tube lower than grade and fill with concrete to grade so that the concrete is larger at the top for frost heaving.

Eh???

 

[jesnic]

When using sona tubes, they are generally smaller in diameter than the hole. If you pour crete into the tube and let it flow over the tube and into the surrounding hole, it will flow out to the bottom and fill in the tapered area at the bottom and fill in around the tube at the top to create an "I" in the ground.

 

[nebraskasparks]

Just tore down a dilapidated pole barn...rotten posts and lousy construction. Used a Woods 14 inch post holer for the new building. 4 ft deep holes with 6 inches of gravel which keeps us away from the frost line here in northern IL. I've also run 600 feet of fence with lots of posts...read the following carefully.

All posts will rot from the surface down to about 8 or 9 inches.
This is where all the life in the soil works and every fence post or pole barn post I've ever busted busted occurred from the surface down to about that level. Bottom line...I put concrete from the surface down to at least one foot below the surface...keeps the rot from destroying all your hard work. Most people throw three or four bags of the 60 lb concrete bags to make this work. Some people mix...most people throw it into the hole and let nature moisturize and set up the concrete. The posts that I've done this to in the past are holding strong.

 

[Duffster]

When using sona tubes, they are generally smaller in diameter than the hole. If you pour crete into the tube and let it flow over the tube and into the surrounding hole, it will flow out to the bottom and fill in the tapered area at the bottom and fill in around the tube at the top to create an "I" in the ground.

Why would you want an "I" and what would be the point of using tubes like this?

 

[jesnic]

There should be no soil contacting the post at any point below, at or above ground level. Even if you pour concrete and set thepost and then cover the concrete with the left over soil appearance sake, the area where soil touches the post will rot. also, if the concrete is left with a small concave (bowl) where the post enters, it will rot. I agree with nebraskasparks, 100%.

 

[LD1]

I forgot to mention that I also run either 3.5" nails or 3.5" screws in the pole that will be encased in concrete about every 4-6". This gives the concrete a better hold on the pole.

I have tore down many buildings and the ones that are just set on a pad and backfilled with gravel/dirt are way easier to pull out than one set in concrete. Especially if the concrete is wider at the bottom. Without the concrete, a little wiggle and they come right out, with the concrete, it is almost impossible. Usually end up with a broken post.

 

[varmint]

I and others have posted before about this, but basically what the others have said about gravel under the post is important: you don't want the bottom grain of the post, no matter how its treated, standing in water- the gravel is for drainage. Conc. around the sides of the post is fine. I think the idea of a conc. "cookie" at the bottom is a bad idea. Nothing rots a post quicker than having it sit in a conc. "vase" that holds water.

 

[MMagis]

Based on what most people are saying, those 100+ year old barns I see still standing are all figments of my imagination.

 

[spc]

I have a Menards Pole Barn. It was built in an area that seems to have a high water table. The poles are pressure treated 4x6. There is a concrete pad at the bottem of each hole and then the holes were backfilled with dirt. I think the dirt in several of the holes is constantly wet and now I have what looks like black mold on the poles near ground level.

Any ideas if this is going to be a long term issue and what I can do about it? Thanks