Trying to build fence on rock

[Anonymous]

I know this is a cattle board, but somebody out there has ran into the same problem I am having. I am trying to dig holes for my corner post 36 inches deep. One area in particular on our place 14-18 inches is as deep as you can get before you hit solid glade rock. Does anyone have any idea how I can strengthen my corner post up at this depth?

 

[la4angus]

Where are you located?
That info may help to give you a half-way
intelligent answer.

 

[Anonymous]

what is glade rock? around here in some places is shale and sandstone, have busted thru 6" an inch or so at a time with a spud bar to get a solid socket and concreted the post into the rock. used a floating brace so no need for a push post. Also some granite boulders from glaciers-no way. seen some big as a car. move the corner. Dug a trench 6' long on top of a hill looking for an edge to a boulder. never did find it. had about a foot of dirt so I drilled 3/4"s hole in the rock and cut the post off. set steel bars into the rock and concreted the post to the rod.

 

[Anonymous]

I am located in the beautiful Ozark Mountains (Missouri).

 

[dun]

I almost asked about that. Welcome to the wonderfull world of the Ozarks. If you'll notice, no fences are straight in the Ozarks and corner posts are rarly at the actual corners. We use primarily hitensile and the fence lines look like they were layed out by a drunk. If we really have to put down a corner post we keep hunting around until we can cat 2 feet of depth and feel lucky for that. I've tried using a hand drill and jack to make the holes useable. Too much work and not enough results. I've used a trick that we did when we were in the desert and putting posts in pure sand. That's using a deadman on both sides of the post in line with pull. I found old disk blades work pretty well because you can put the cup in the direction of the pull.
We're just south of Lebanon and around here if ti's only the size of your fist we consider it sand. Stones are head to washtub size. The stuff in between is gravel. A rock has to be the size of a truck or larger to be considered a real rock.

dun

I am located in the beautiful Ozark Mountains (Missouri).

 

[Craig-TX]

Around here it's mostly limestone. The old fashioned way is to take the crowbar and get after it. When you're going thru solid rock it won't break into nice chunks. It will flake and powder and you have to clean out the hole often. It's like cutting wood with an ax, in that you can watch a man for one minute and tell if he's done any crowbar work in his life. The key is to let the weight of the crowbar do the work, be accurate with each lick and don't think you're going to get a hole dug in a couple of hours. It's very slow and it's definitely winter work.

If you've got much of a project and you're doing it yourself it's worth renting a compressor and jackhammer. For line posts a jackhammer is great, just order T-posts without the fins and drop them in the holes. They won't go anywhere plus they'll tighten up on their own over time.

Some of the old hand-dug wells around here are well over 20 feet deep. They were dug back in the 1800's. I've often thought about how much work that must have been. They were bound to have had dynamite, but still…

Craig-TX

 

[D.R. Cattle]

Hard to understand these problems. So sandy here, we drill holes with an auger in about 3 seconds, slap a post in, and the hole starts to cave rather quickly. Takes a couple of good rains for the sand to compact and sturdy the post. The only rock we have is ordered by dump truck for driveways, most of which is excavated fossil coral or "coquina" rock or crushed seashell.

 

[dun]

When we were in the Mojave Desert it was the same way. Learned to soak an area very thoroughly with water before attempting to dig a hole. A 3 foot deep hole would be about 20 feet in diameter at the top. In Washingtin it was heavy clay very little rock, no sand. In the CA central valley in a 500 foot run of fence you would run into everything from pure sand to solid rock. But this stuff here is the most frustrating I've found. A lot of T-posts are only in a couple of inches, so you just either stick them in closer or hunt around for a place you can get them in deeper. 12'" is considered pretty darn good, 18" is an answered dream.
A freind of mine came down from IL and even though I had described the soil(?) around here I don't think he really believed it till he saw it for himself.
dun

Hard to understand these problems. So sandy here, we drill holes with an auger in about 3 seconds, slap a post in, and the hole starts to cave rather quickly. Takes a couple of good rains for the sand to compact and sturdy the post. The only rock we have is ordered by dump truck for driveways, most of which is excavated fossil coral or "coquina" rock or crushed seashell.

 

[eric]

Seems I saw on some website when I was building my fence that some folks use rock for the corners. If I recall, they would put the corner post in as deep as they could, then put some wire mesh around the post, about 2 ft diameter, 3-4 ft high, and then run the 4-5 strands of wire out about 100 ft or so, letting them hang loosely, then fill the wire mesh up with 4"-6" stones they either bought or found around the property. I think that a 2 ft diamerter basket fill with solid rocks would probably hold most corners pretty well. Does this make any sense?

 

[dun]

That's a fairly common corner around here, at least it was 40-50 years ago. No one seems to do them anymore. Sure have enough rocks to build some substantial ones. If iny one were they don't have rocks want to give it a try, let me know and you can come up and get all you want. Won't find many of those little ones around here though, mostly head sized on up.

dun

Seems I saw on some website when I was building my fence that some folks use rock for the corners. If I recall, they would put the corner post in as deep as they could, then put some wire mesh around the post, about 2 ft diameter, 3-4 ft high, and then run the 4-5 strands of wire out about 100 ft or so, letting them hang loosely, then fill the wire mesh up with 4"-6" stones they either bought or found around the property. I think that a 2 ft diamerter basket fill with solid rocks would probably hold most corners pretty well. Does this make any sense?

 

[Craig-TX]

Seems I saw on some website when I was building my fence that some folks use rock for the corners. If I recall, they would put the corner post in as deep as they could, then put some wire mesh around the post, about 2 ft diameter, 3-4 ft high, and then run the 4-5 strands of wire out about 100 ft or so, letting them hang loosely, then fill the wire mesh up with 4"-6" stones they either bought or found around the property. I think that a 2 ft diamerter basket fill with solid rocks would probably hold most corners pretty well. Does this make any sense?

Most of the times I've seen those they look pretty old. I wouldn't trust one that was only two feet across. I suspect they were built when the farmer was clearing his field of rocks anyway (a never ending job on some places) and he made corners out of them instead of just making rock piles. They are usually hog wire holding up a round stack, like you described, but the column would be at least four feet and up to six feet in diameter. One thing's for sure, they aren't going anywhere either.

Craig-TX

 

[dd]

Where I'm at in IL we run into the occasional fist sized rock. Anything bigger than that and usually it turns out to be an old foundation from something. I can think of only one rock on the entire farm big enough to sit on.

 

[Bernard]

Years ago I helped build a couple miles of fence on just about pure rock. We rented a gas powered jackhammer and drilled holes for the T-posts about 6" deep at least, hopefully more. If we could leave the fins on, we did; if not, we removed them. Gravel and sand kicked down into the holes while wiggling the posts settled them pretty well at the time, and later on they got rock solid. We used oilfield pipe for corners, digging as deep as we could with the jackhammer and concreted them in. I don't think we ever got one in over a foot deep. We then came out in line with the pull some 6' and drilled a 6" hole at a 45 degree angle sloped back toward the corner post. If the hole sloughed off or caved in (rare), we went out a little farther. We put a piece of 3" pipe into this hole running up and back to the corner. This was cut off flush and welded. After we were finished it seemed like it would hold up OK, but I quit soon after and have never been back, so I can't guarantee the long term results.