Sand or gravel around pole barn poles?

UP Oliver

Member
I posted yesterday regarding my pole barn. I have heard about putting stone around poles and also about putting sand. Is one better than the other and if so why?

I would have to buy stone but I have a lot of sand available for nothing.

Thanks.
 
I always thought sand did not pack as tight as gravel. Plus the gravel will allow the post to stay some what drier. Also gravel is much easier to pack/tamp around the post.
 
My building has crushed rock in the holes. Idea is that the rock allows some breathing to get rid of excess moisture, and the jagged shapes give a wedge effect against the post. 10 years and still OK.
 
What ticks me off is a lot of towns say you must use cement. That is the worst thing cause the pols rot off!! One way you should ask this question is you need to TAMP the soil or gravel around each pole. I use a Shale bar and pound the soil in about one foot at a time. Posts or poles never move after that.
 
I found pea gravel, around the 4"x6" fence posts, on the corrals of this former horse farm, when I bought it in 2000. I pulled them up and the 3' that was in the ground, was much like new, after 10 yrs in the ground, in fact that portion was better than the exposed tops. I reused better than 80 posts, on my perimeter fence, but didn't use gravel, I used our sandy soil, and have some rotted off with the fence wire holding them up. I was not very smart, and couldn't see what was right before my eyes. Lesson learned, I now fill the holes with pea gravel. I am getting too old to be tamping posts again, but have no choice.
 
Was told by a ole long time farmer around here to use pea gravel and posts will last a long time. SWMBO decided was to much extra expense so now have many many post needing replacement as rotted off. You know who is gonna have to do the work of replacing them.... not her.
I recommend the added expense and get the gravel. Could save many hours of labor and repair price down the rode. In the end is your time and money.
Good luck,
Norm
 
Are you guys talking about treated or untreated poles? More to the point, do the same principles apply to treated poles and posts?
 
The building inspector here requires pea gravel, which I assume is for drainage. You need a concrete plug about 12 inches in diameter and 8 inches thick at the bottom of the hole. After the post is set, the first foot of fill is pea gravel. They don't specify what you use to fill the rest of the hole.

What I did was to pour half a bag of dry redi-mix concrete over the pea gravel. That really locks in the post so it doesn't move around while you finish filling the hole. I suppose it could contribute to upheaval, but I've had no problems with that in the 12 years since I put up the building. I think the single most important thing to prevent upheaval is to make sure the site is properly graded and you have good drainage around the building. If the ground is dry, it's not going to heave.
 

depends on how clean your sand is. in order to drain well enough to keep your post s dry it needs to be fairly clean, with a minimal amount of fines. if you need to get an idea of what clean sand is like, both septic sand and the sand used on roads has to be clean.
 
I had to go reread your other post about your post, LOL. I am a not quit understanding yet, did you put concrete around the post when you set them? When I set post I like to nail a couple pieces of 2x4 to the bottom of the post horizontally, frost won't heave them out. My grandfather used concrete to set his post and most made it 25 to 30 years, but I think the treating is not as good any more. Tom
 
Just a thought. We all know how hard it is to get concrete removed from form boards, What would happen if one was to use a sand and cement paste to coat the buried part of the post before setting it? One could even wrap it in chicken wire before plastering it. Or is asphalts driveway sealer the answer?
 
Depends what kind of sand you have, I would not use "blow sand" if you have good screened sand it will pack better than gravel, all depends what yuo have
 
It really depends on your soil type and drainage.

If you have good deep drainage a pea gravel sand mix works well.
If you have hard pack clay with little or no deep drainage all you did by putting pea gravel in the hole is build a clay lined pond.

If you want the poles to last the first thing you need to do is buy the right wood.
If you buy wood treated for ground contact UC4A treated to CCA 40 (normal lumber yard treated wood) you got the wrong stuff and it will rot out no matter what kind of backfill you use.

You need at least UC4B treated to CCA 60. If you can find UC4C that is even better.
 
sand being finer than gravel is more apt to hold moisture and then freeze--thus gripping the pole and lifting it.
mooring piles in tidal waters are placed with the butt end down in the bottom--so when ice forms on the water surface and it rises with the tide the diameter of the pile gets smaller and the ice just slides up
the same principal works on a pole in the ground also--butt end down.
 
That's kinda what I thought too. Gravel or sand is lazy man's way as it's self tamping. I use dirt. I replace hundreds of fence posts and in good hard ground the lower portion is most always sound. People forget it takes two things for decay. Moisture and oxygen.
 
Right you are, Howard! I have pulled out 100 year old hedge posts too and they always rot off at ground level while the part below ground is still as good as new.
 
The power companies just put back the dirt that comes up when they bore the holes for new poles and the poles last for decades. If you are in an area that has ground frost do not put concrete around the posts as this just gives the frost something to grab and push the post up.
I would go ahead and use the sand but be sure that you tamp it in good. Don't worry about the water around the post causing it to rot. The fungus that causes wood to rot can not live in water and that is why pier pilings that are under water always last for many years.
 
Thanks for all the responses, here is some more information.

First of all, my concern is with the poles being gripped by frozen soil and being lifted up. I have 3 ply laminated poles from a supplier in Wisconsin; they have been treated for in ground contact.

When I started this whole project, I put a test hole down to about 5 feet and did not have any water in the hole. The soil was seemed like what I would call silty clay. It was damp, but did not come out in clumps. Both the building inspector in my county and the experienced contractor that has put up pole barns in my area and now works for the building supply store advised me to put the original dirt back in the hole. The inspector has not seen my site, the experienced contractor has. This guy is really nice and very helpful.

Since I did not hit any water (in August of a fairly wet summer) I assume that the site is OK in that regard and once it is done and graded that I should not have problems with wet soil or soil heaving my poles. But my problem is with what has happened with the weather since I started.

I have put 17 holes in the ground (out of 46) and they all had two 80 pound bags of quikrete put in there wet, then tapped flat. The pole goes on the concrete when it has set. The bottom of the concrete in these holes will be 56 to 60 inches below the finished grade. Code is 42 inches.

I have 11 poles in with 3 or 4 rows of girts, and the poles are braced. We had 3 inches of rain here Wednesday, and then temps in the 50's, frost a couple nights, since then. Not good drying weather. So I pumped a bunch of water out of there; I had stripped the topsoil out so the area was a little lower than the surrounding ground. The six holes without poles were full of water. The rain went in along my poles that are installed and created a bunch of muck in some of the holes. It was the same soil that came out of the hole, and I tamped it with a 4 x 4 after every 6 inches of fill. I am worried that this muck will not dry out really well and freeze in December and lift the pole. I could probably dig that soil out by hand for all the poles in a few hours, and I would rather do that now after 11 poles instead of after 46 poles.

In the coldest part of winter, there will be a lot of snow around the outside of the building and the dirt under that snow will be easier to dig in then than it is in the summer. I buried our old German Shepherd on January 29th last year and had no problem digging a 3 foot hole under the snow. But the building will not be heated so the cold will be able to penetrate inside. Maybe with the warmer soil on the outside of the building the ground around the post will never freeze? A contractor friend of mine stopped by last night and suggested putting a piece of rigid foam insulation along the green board flat out toward in the inside of the building to prevent frost from penetrating along the poles. I thought I read somewhere about that being done in Canada.

I can put stone in around the poles, but I worry about creating a clay lined pond basically, like John in La mentioned. The sand I have here will drain well, and pack well. But if it is surrounded by clay the only benefit would be that any water would be further down in the hole away from the cold at the surface.

I have an email into the building inspector and the experienced contractor right now. When these guys get back to me I will go from there. I feel kind of bad questioning these guys about what they told me to do, but if they saw the muck in these holes I would guess they might rethink the advice.

Anyway, thanks again for the help and advice. I get the best information I need all the time from the people on this site.

Thanks, and sorry for the long post.
 
Just curious as to why there is a building inspector for a pole barn, or any other private building for that matter, we don't have any building inspectors for anything non commercial and never have. The only inspection we have is installing a septic system, other than that you can build a mansion or a slum and everything in between with no interference, what it winds up to be is between you and your insurance company.
 
Sorry if this sounds a little harsh but.......

You had both a local building contractor that has built pole sheds in your area in the past and a local building inspector that knows your area; tell you what they think is best for your area; yet you second guess and ask out of state; different climate zone; different soil type; guys on the internet what they think is best.
Once again while it is harsh; that statement may drive home the point to where you trust your local guys.

Since your soil type is such that it will pond water you want to refill with the same soil. Yes it will be muck when it rains as the soil is not packed good. You can not pack it like nature can.
The only chance you have of packing the clay soil is in 1 foot lifts flooding the soil and letting it dry out between lifts.
That is not production feasible.

So put the original soil back in the hole; pack it as well as you can and let nature do the final packing for you. As the moisture drains down threw the soil it will pull the fine parts of soil with it packing it tighter and tighter.

If you want to try and stop uplifting make the hole wedge shaped (bigger at the bottom). Pour a concrete footer in the bottom of the hole and let it set up. Drill a hole threw your post a few inches up and install a large piece of rebar; then pour a foot thick piece of concrete around the bottom of the post. The rebar will hold the post tight to the concrete; and the wedge shape will not allow the whole chunk of concrete to move up in the hole.
A couple pieces of 2x6 the length of your hole width nailed across the bottom of the post will substitute for the rebar. In fact if you use 2x6 you can forget the chunk of concrete and just backfill with soil.
If you use the concrete do not pour the footer and this chunk of concrete at the same time. You want water to be able to drain out between them.

I can not stress enough getting the right wood. You said it is for below ground contact but then said it is laminated poles. I assume three 2x6's nailed together. If you want to second guess someone this is the place to do it. Can you quote; or even bother to ask; what level of treatment; and what chemical was used; to treat this wood. If you do not know this is the guy I would be sending a second guess email to.
You can buy poles with no fear of rotting out. We use them for docks in saltwater applications. The cost of them is the limiting factor for use in a pole shed.

Now once you get the poles in pile a wedge of dirt around the pole to where water drains away from the pole. You want as little water as possible going down in the now filled hole.

Look at where telephone poles rot.
Right at the soil surface and the top of the pole.
The top is not a problem for you as a roof will be installed but the soil surface is where you need to protect.

Hope this helps you. Sorry I was so to the point but what you are going threw is a common problem.
 
That's a concern in N MN. If you put a porous material around a pole it will retain water and when it freezes it will jack the pole right out of the ground. I think it's best for us to put the clay back in.
 
We always use limestone screenings. Packs tight but drains very well. I'd be a little leary of sand being able to drain over time.
 

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