Building a fence - Backhoe or Auger?

[Apsterbobed]

Analog I usually try to have about an inch of space or more around a pole. It's sometimes hard to get all the holes in a perfectly straight line so then the poles end up being off set to one side a little in the hole to keep everything looking straight. Personally I would probably use about a 9" auger on 4x4 posts. That gives enough room to move the post around in the hole to keep a straight fence. What I usually do is set my corner posts and then run a string line between to help keep things straight. For drilling I usually just mark where I want to dig the hole but for setting posts I space the string 1.5" off to the side and then measure to set the posts. That way if one post is a bit out it won't push on the string making all the rest of the posts a bit out. If you use crushed rock you don't have to pack the posts at all. Just wiggle them once the holes are full of rock and you can feel them tighten up. If you don't like where you've set your post they are easy to change. Just lift it out and clean out the hole and reset your post.

I don't like using concrete around post because quite frankly it's a lot of work. If you make a mistake it's even more work. I'm not so sure that concrete keeps water away from the post. Every time it rains the water runs down the post and in between the cement and the post. Any cemented posts I've seen rot off in the first four inches of cement. I'm just putting posts in the way the power company's do. I really like the self tightening action of crushed rock.

When you say crushed rock are you talking about 3/4 ish crushed stone or crusher dust (the fine flakes of stone)

 

[Brad_Blazer]

I have a 4" auger I use for landscape timber line posts. I pour dry sand in to fill the small space with minimal tamping. I wiggle the post to get the sand to settle and get it as plumb as I can. Wiggling in a circle will make the post rotate in the opposite direction in the hole to align the flat sides as you want. For corner posts the added rigidity of a big slug of concrete is a plus.

I got the sand idea after setting a 40' flagpole that sits in sand inside a metal tube embedded in concrete. Commercial / Architectural Flagpole Installation Instructions

 

[analog]

Thanks for the extra information pmsmechanic. I like the idea of being able to reset the post as needed, and have it self tighten as you wiggle. If it isn't sturdy enough, I can always dig out a little and concrete near the top of it.

I'm kind of surprised there isn't some attachment you can throw on the FEL bucket to tamp down ground... who wants to do stuff manually if you have a tractor?

Brandi, that would be great, but for this small of project I'm not going to cut my lines and install an auger on the hoe end. By the time I was done with that, I'd be halfway through. Fortunately the land is near, if not perfectly level and I think a 3 point auger will do just fine.

Brad_Blazer, the link you provided I'm sure would make a helluva post, but they're running metal into the hole, not wood. Note the line in the instructions " Be certain that sand is well compacted, otherwise pole may shift at a later time." I wonder why they even use sand?!

I think I'm going to buy a 9" auger. I found a John Deer PHD100 on craigslist today for $500. Anything I should watch out for when buying used?

 

[Gary Fowler]

I have always completely encapsulated my fence post in concrete and never had on to rot even a little. I use pressure treated 4x4 from Lowes and after 20 years they are still solid. I used dry mix Sakrete, put a shovel full in the hole first then the post and pour it around the post dry. I then final level the post and then just add a bit of water and mix it with a long steel rod with pointed end by tamping all around the post to mix the water. Note: Don't use too much water, about a quart per sack of concrete is plenty. It doesn't have to be thoroughly mixed because there is usually enough moisture in the soil to hydrate the bottom part. I put enough concrete in the hole so that is it at least 2" higher than surrounding dirt and then trowel it on a 4 way slant so any water runs away from the post. Any water that might seep down the post is free to evaporate back out and the concrete keeps all the soil moisture and fungus away from the post.

PS: I had to pull a couple of them up once and they were all solid concrete all the way around and very strong. It took me a while with a sledge hammer to break it off. The post was solid and I re-used it.

 

[Ed of all trades]

I answered in my other post that way because you said you wanted to put crete around the posts. I would not use crete and would NOT, NOT use crushed rock. The crushed rock will give water a place ti stand around the post causing rot. Dill the hole with a 9" auger 2' deep and put a small amount of dirt around the post and pack it down with what you have, digging iron, pipe with end cap, or even a small tree about 3' across at the bottom. repeat the process until hole is full. The old timers say you did not do it right if you did not have to get extra dirt from somewhere to finish the hole. It is work but the posts will not move. You can also use the clamshell diggers and arm power, it is only around 50 posts and you wont have to go to the gym.

 

[analog]

I don't understand how crushed rock would be any different than dirt, except that the particle size is bigger. I can see how one would say that water could fill into a concrete hole and stay until evaporated. It seems like everyone has had some success doing all four things - concrete, rock, sand and soil. I like the idea of rock, as it is easier and less expensive (although not as inexpensive as soil!), but I'm going to read a few books and see what they have to say before making the final decision. The important thing at the moment is auger vs. hoe, and I think I have the answer to that... everyone seems to agree that an auger is the way to go, even with the one poster saying I should ditch the hoe bucket and replace it with an auger!

 

[CDN Farm Boy]

Another vote here for the auger. Last fall I put in about 40 posts. Corners were old hydro poles set 4' deep so they went in with the BH. For the line posts (4-6" round cedar) after the first few with the BH, I switched to driving them by hand with my 16 lb post maul and was far happier with the results.

I'm with Brandi and one other poster about using an auger on the end of a BH, mini-ex or on a skid steer. The control you have is SO much superior compared to using a PHD on 3pt hitch that its worth every penny of the rental fees. Once you've tried it, you'll never use one on the back of a tractor again.

 

[pmsmechanic]

By crushed rock I mean 3/4" crushed rock with no fines in it. Other gravels work too except they aren't as self tightening as crushed rock. What happens is as you wiggle the post the rock settles in the hole and around the post and everything gets wedged tighter. You can actually feel the post tighten up. Later as the wind massages your fence it gets even tighter. I'm talking about a yard type fence with boards on it. Obviously fences with less wind resistance wouldn't get massaged to the same extent.

I don't mind the idea of using concrete either except where I live it shortens to life of the post. I would say also to observe the way that the power company's set power poles in your area. They have a vested interest in making the post last as long as possible. I just applied the way that power co's set posts in my area and applied it to my own use. It saved me time and money. Dirt and sand work too and I have used both. Crushed rock is just easier and somehow that appeals to me.

Obviously I've high jacked this thread to some extent. My apology's.

 

[analog]

The power company actually just set some poles up down the street from me. They did miles worth of replacing, dozens of poles, at least. I don't know if they were upgrading or replacing due to problems, but I'll walk over and see if I can figure out how they did it.

I would think with crushed rock, eventually dirt will work its way into the cracks anyway, so what's the difference between that and dirt, except it fills the hole and compacts itself, as you say. I don't see how, if needed, adding a concrete topper on top of the rock would be a problem. Many people say use gravel underneath the post so that it can drain.

I will be using pressure treated posts, by the way. That was the plan all along.

As for the auger on the end of the BH, would it be preferable? Probably, but it's also a lot more work than just throwing on a 3 point auger, and again, I'm in the unique position (for my area anyway) that my land is flat.

 

[bindian]

I have always completely encapsulated my fence post in concrete and never had on to rot even a little. I use pressure treated 4x4 from Lowes and after 20 years they are still solid. I used dry mix Sakrete, put a shovel full in the hole first then the post and pour it around the post dry. I then final level the post and then just add a bit of water and mix it with a long steel rod with pointed end by tamping all around the post to mix the water. Note: Don't use too much water, about a quart per sack of concrete is plenty. It doesn't have to be thoroughly mixed because there is usually enough moisture in the soil to hydrate the bottom part. I put enough concrete in the hole so that is it at least 2" higher than surrounding dirt and then trowel it on a 4 way slant so any water runs away from the post. Any water that might seep down the post is free to evaporate back out and the concrete keeps all the soil moisture and fungus away from the post.

PS: I had to pull a couple of them up once and they were all solid concrete all the way around and very strong. It took me a while with a sledge hammer to break it off. The post was solid and I re-used it.

Gary,
This is the exact way I set posts.
hugs, Brandi