Fence Posts

[Arcane]

I need to set 40 or 50 cedar fence posts in flat but rocky soil, mostly potato to basketball sized granite rocks. I've learned that shovels don't work on this property, so I've got a Woods 80X backhoe on a B7800 that can dig through most everything. I can dig the post holes with that, but working alone, I'm anticipating it being difficult to set the posts upright in the big holes that the BH will make, and tamp them solid.

A PHD with a 9" auger would make nice neat holes, with little tamping required afterwards, if I can get it to work with the rocks. And that is a big IF. I'd like to try one first, but no local rental shops have them (perhaps they've all learned through experience).

I guess my question is this: if I already have a tool that will do the job (the BH), but perhaps not as well as another tool (the PHD) am I crazy for thinking about getting the other tool?

 

[EddieWalker]

How small of a bucket do you have? If you decide to use the backoe, then I would think that digging the hole in the same direction as the fence is going will give you two solid walls in the direction that the posts will want to lean agains.

I have a 12 inch auger and have found that it's too small. If I get the hole drilled in the exact right spot and I don't hit anything on the way down to send it off course, the 12 inch hole is just about right for a 6x6 post. If I miss my mark, hit a root or a rock, and the hole agles off or just slides over, then I'm digging with the clamshells to get it where I need it.

In in East Texas, and cedar doesn't last very long here. It rots out right at the soil line. In my case, I have seen it start in about two years and by year 3 it's gettting pretty obvious. I've also seen cedar fences on the West Coast that have lasted 20 years without any sign of rot.

Eddie

 

[Arcane]

16" bucket, and its a BH70X, not 80X. Our local red cedar, Juniperus virginiana, lasts 20+ years as a fencepost up here.

 

[MMagis]

This is just me, but if I had to set posts in a hole dug by a backhoe, I wouldn’t. I know a lot of folks do it, but I have a hard time believing they could be tamped well. I could be wrong. I’ve set more locust posts than I could ever count in holes dug by 9”-10” augers. I really can’t understand how a 12” auger could be considered too small. I only use a 12” on corner posts. Of course, I string my lines and make sure I don’t wander. I think a PHD would be the better tool, but I can’t say it’s would be worth cost of buying one. Renting would be perfect, if you could find one. Any farmers around that you know? Many have post drivers and may be available for hire. Can you use T posts for the majority? They would drive a lot better than wood and you could do it yourself very easily.

 

[gwdixon]

A PHD will come to a screeching halt on the boulders you say are a factor. A BH is the only way to go in your case.

After the hole is dug nail a couple of 2 x 4s at a 90 degree angle to act as a tripod with the post. One of those square post levels will work on a round post.

Then backfill, check the level, remove the 2 x 4s and you are done. Granted, I did this with a concrete fill but it should work with dirt and rocks.

The BH bucket can be used to do the tamping and will provide a lot of downforce.

 

[Luremaker]

I have very rocky soil and I always drive fence posts in. No tamping required. I have a shaver HD-8 post driver. I have no problem driving 6"-7" diameter posts in my soil in early spring before the soil has dried up and hardened . On occasion I'll hit a large rock and have to move the post a little to the left or right but no big deal. Do a search on post drivers here on tbn lots of info.

YouTube - Post Driver Tractor Attachment

 

[MMagis]

A PHD will come to a screeching halt on the boulders you say are a factor. A BH is the only way to go in your case.

After the hole is dug nail a couple of 2 x 4s at a 90 degree angle to act as a tripod with the post. One of those square post levels will work on a round post.

Then backfill, check the level, remove the 2 x 4s and you are done. Granted, I did this with a concrete fill but it should work with dirt and rocks.

The BH bucket can be used to do the tamping and will provide a lot of downforce.

Sorry, that won't work at all without concrete. "Tamping" with the BH bucket won't do any more good than stepping on the dirt. I tamp with the handle end of a 10 lb sledge, and still don't think I get them tight enough. A 20 lb pointed spud bar works well, that's how much it takes to tamp one in properly.

 

[Haoleguy]

Luremaker has the best suggestion if a post driver is available to you. Previously on a fencing project about 20yrs ago I did use a PHD and it was a real fight to get the holes dug and posts in. I won't be doing that anytime soon unless I have one of those heavy duty PHDs described by others on this board that are described to go through anything. More recently I have done what you are planning to do in what is probably the same soil type. About 4 yrs ago my backhoe was used to dig 4ft post holes as I didn't have a nearby post driver to rent. I set my 11 cedar posts(all naturale) using the tripod 2x4 guides as gwdixon suggested in the Spring....took about 8hrs to dig and set posts. With a combination of depth, rock placement, tamping and rain the posts firmed up pretty well before adding the 7' high welded wire fencing. I have not had any problem with these posts over the last 4 yrs. As Eddie mentioned the eastern red cedar is not as bullet proof as one thinks as it is only the heartwood that is decay resistent. However, as the non-heartwood decays soil fills in the voids and keeps the fence line relatively strong.....assuming you have a good diameter of heartwood. I did come across an Oregon State University study on treated and untreated fence posts and it was the untreated western cedar, black locust, and osage orange that are the bullet proof ones. Over the past few months I've been doing my homework in preparation to run a 6K length deer fenceline and in that case I will be using a post driver, with rock spike, black locust posts and woven wire.........Gary

 

[two_bit_score]

...............In in East Texas, and cedar doesn't last very long here. It rots out right at the soil line. In my case, I have seen it start in about two years and by year 3 it's gettting pretty obvious. I've also seen cedar fences on the West Coast that have lasted 20 years without any sign of rot.

Eddie

I think there is someone around ********* selling the eastern red cedar posts and people are saying they have had good luck with them. The 'regular' hill country cedar posts don't last very well in east Texas.

 

[RPW]

If you have to use a BH then when you back fill wet the ground and dirt. After backfilling and tamping let stand for a couple of days at least. That will allow the dirt to settle and has worked very well for me.

Good luck.

 

[gwdixon]

Sorry, that won't work at all without concrete. "Tamping" with the BH bucket won't do any more good than stepping on the dirt. I tamp with the handle end of a 10 lb sledge, and still don't think I get them tight enough. A 20 lb pointed spud bar works well, that's how much it takes to tamp one in properly.

If you weigh 2000 pounds I might agree with you. Putting the bottom flat part of the bucket on the ground and applying downforce enough to lift the outriggers applies a tremendous amount of pressure.

A "spud bar" is indeed a good tool for working around the post to get out any air pockets. It will do a fine job on a small diameter hole.

The BH is just a simple way to tamp down the large area that is dug up using the bucket. Using a bar is not reasonable in a large area if your muscles get as sore as mine do with a task like that. A couple of other posters have mentioned their success with this method.

 

[Arcane]

I can rent a gas powered compactor for $35 after I get all the posts in. I think that's the way to go, unless I locate a borrowable PHD before the ground thaws. Thanks all,

R. Kane

 

[Haoleguy]

I can rent a gas powered compactor for $35 after I get all the posts in. I think that's the way to go, unless I locate a borrowable PHD before the ground thaws. Thanks all,

R. Kane

Your comment suggests that you want to do this now!? Unless you are in an unusual microclimate in MA you're probably looking for a good thaw to do this. With the cold temps we are getting it might take several very warm days to make the ground workable. I have not tried to use a PHD on frozen ground but I can tell you that my backhoe acts like it hit concrete.

 

[Ken45101]

A tractor mounted PHD is not going to work against granite boulders. Purchase shear pins by the pound and make sure you get the volume discount

A skid steer mounted PHD with a rock cutting tip might work (skid steers can exert down pressure, tractor 3pt hitches do not).

I agree, the best approach is a post driver.

Ken

 

[MMagis]

Using a bar is not reasonable in a large area if your muscles get as sore as mine do with a task like that.

I agree, but that's my point. The down pressure from the bucket is in no way equal to the pressure of a spud bar, and it can't get close to the post. I'm sure it will hold a non functional post up fine. I sure wouldn't trust it to hold in livestock. Any pressure at all and it will move.

 

[quicksandfarmer]

I live close by, just over the RI boundary. I have similar rocky soil. I have a Leinbach PHD with 9" auger and I have used it to drill a lot of fence post holes. We have a lot of rocks that are between softball and football size and the auger will pick them up and throw them out of the hole. The rocks tend to be rounded so I don't have a lot of trouble with the auger getting stuck; I haven't yet broken a shear pin. I generally find that if a rock can fit through a 9" hole the auger will move it. But there is no magic, a 12" rock isn't going through a 9" hole.

If there's a big rock where you want to put a fence post your choices are to make an even bigger hole, or put the post somewhere else. There's no way around that.

I find 9" makes a nice fence hole, big enough so you have some wiggle room, small enough so the post is supported by undisturbed soil.

I've had good luck with local red cedar posts. I used three western red cedar posts from the lumberyard for a project near the house and they started rotting at ground level within a couple of years. I've got some pressure treated posts the previous owner put in that are at least 20 years old that are still sound.

As long as there's no snow on the ground and the ground is dry enough this is a good time of the year for putting in fence. It's much easier when the vegetation is dormant.

 

[Arcane]

Now That's what I needed to hear: someone working with the same soil matrix. Thanks. Want to rent me your Leinbach? Didn't think so. But thanks again. RK

 

[ManAtArms]

I'd vote against the backhoe option unless its your last resort. I think you mentioned 60 posts. I installed a similar count using a backhoe this summer. It displaces a giant amount of soil. Cleanup is a pain, and you have a bigger hole to fill in when setting the post.

See if you can rent a post driver, and if too rocky, a post driver with a rock boring attachment. Many of these can drill into solid rock. Another alternative is to rent a belltec TM48 for boring the holes, then setting the post in by hand or driving them with a separate driver.

Hope that helps.