I tried to dig a few postholes yesterday, and each time I hit rocks about 2-3’ down. How do fence installers deal with rocks and roots when digging post holes? I had the luxury of relocating when I hit obstacles, but fences require holes every 8’ in a straight line.
I imagine there’s a lot of digging involved. Do you need to sink them deeper than 3’ or are you routinely stymied at 2’ or less?
I used a jackhammer when I ran into limestone and caliche at a foot under the surface, but I’d bet that a lot of the fence companies around here just dig shallow holes and rely on the adjacent posts to keep the fence up.
Man, I had to dig post holes for the backyard fence one summer to earn camp money, and I didn’t have the luxury of moving when I hit rock, because there was limestone about 1 foot down everywhere. Not totally solid, but large chunks that 14 year old me had to cut through with post hole diggers.
Fun stuff.
When I was building decks and fences, we used a guy that had an auger on a little tractor. I don’t know of anyone who actually digs post holes by hand unless its only one or two.
You need to go down 3’ at least because of frost line. If you dint’ get below that, you more then likely will have posts the heave in the spring, are not secure etc. Unless you live where there is no winter. 
We had 2 fences installed over the past 20 years, and both times they had a guy dig 30 or so holes by hand. Same with about 5-8 holes for a small deck. And yeah - 3’+ to get below frost and avoid heaving.
The first time I asked him what he did when he hit rocks or roots, and he said he just “dug them out.” But I didn’t ask exactly how he did that. Yesterday, when I got 2’+ down and ran into fist sized rocks, I could lie down, reach down the hole up to my armpit, and scrape and claw the rocks out with a hand trowel. Frigging exhausting! I couldn’t imagine someone doing that for more than a couple of holes. Plus, your arm is only so long!
I was wondering if they might use a long (4’?) cold chisel and a sledge to bust up any impediments.
Years ago we tried using an auger. Man, when that blade hit clay, it bit, and the top would start spinning. My dad aptly called it a man-killer!
These work pretty well: Digging Bar
I normally use a post hole auger on my tractor 
Maybe I should state that I don’t approve of placing fence posts in shallow holes, just that the local companies may cut corners.
FarmerChick, we don’t have winter around here (the frost line is set at a nominal six inches, but we rarely get below freezing for over thirty hours at a time.) All the same, I’d sink the line posts to at least eighteen inches, corner and gate posts at least two feet and deeper if I could. Most types of dirt move as they get wet and dry out. Digging deeper puts the fence post in more stable dirt. It also provides more leverage to keep the posts vertical.
That digging bar looks like just the tool. Thanks.
When we had a fence put in, there was something like a $500 ‘rock’ line item that would kick in to pay for jackhammer time if they hit bedrock. Fortunately we don’t live in the half of Austin that’s on solid limestone.
(We live in the half that’s on expansive clay.)
I searched in my neck of the woods for an auger for rent and found this:
At $40 per day it sounds like a good deal if you have a buch of holes to do…
Now ya got me thinkin - for $250 I can rent a backhoe for a day. Sounds like a birthday present for ole’ 2gig comin up…
Around these parts, we call that a “spud.” Does anyone else call it that?
Whatever one calls it, it’s a serious tool.
When I was a kid we called it a “caliche bar,” but that might just be because we bought one when we hit a layer of caliche mixed with limestone rubble in my folks’ back yard.
When I was a landscaper, we called it a spud bar too.
I do building work, so often have to dig holes 900mm deep. Roots get chopped through with a sharp spade, rocks get chipped at with a 6ft heavy crowbar - pointed at one end, flat at the other. Recenty I dug 9 holes, the first 300mm was top soil, the next 300mm was solid lava, then the last bit was sand-like. Yay!
The guys I’m involved with do several hundred km of stock fencing a year. There are times when they do fencing with hand tools, but they use their post driver as much as possible, this one since the early 90’s Fairbrother III. It has the optional auger motor for hard soil and the occasional hole into their limestone prone area. For work in areas with rock, a rock spike is recommended.
The work rate with the banger can be 30 posts an hour with 2 guys, once the strainers are in, the line wires run and the posts laid out.
I once blasted a few post holes where there was solid limestone, but I need to re-think my technique, as I made too big of a crater at the bottom of the hole :smack:
I rented one quite similar to that about 20 years ago, trying to save on the installation costs of a fence. Got the 2-man model, and had 3 other guys to help me.
We ran into a ton of clay, and after no more than 2-3 holes, the other guys were offering to contribute to the cost of installation if they didn’t have to dig any more holes. When that auger hit clay it would bite, and the top would start spinning. Far from the easy job I anticipated.
When the guys came in to install, one guy dug all 30-40 holes in one day with a manual digger.
freck - now that you mention it, I’ve heard the term “spud bar” before.
Out in Colorada we call that a Tampin bar.
I have put in maybe a thousand posts for ranch fences over the years as a kid making summer money using an auger on an old 9N, and here’s something most people don’t know: The wedge end is more important in tamping(packing the dirt around the new post), than the flat end is.
And one funny little thing. A neighbor borrowed the auger one day for a hole, didn’t control it , and screwed it right into the ground up to the gearbox. It took him 2 days to dig it out, when diging the hole in the first place manually would have taken about 15 minutes.
I put in a new fence around two sides of my back garden three summers ago. I needed to dig about 20 holes. The hardest part, actually, was removing the chunks of concrete and Metpost spikes that the previous, unsuccessful, fenceposts were set in (and had snapped flush with the ground.
For the actual digging, I did it by hand using one of these (or something similar). The ground in England doesn’t freeze in winter (at least not more than a couple of inches) so I didn’t have to worry about frost heave, but we’re in a windy spot so I dug to a depth of 2ft 6in and concreted the posts in. I pity the foo’ who has to dig that lot up. 
If I hit big rocks I crowbarred or pickaxed them out. Roots I sawed through using a pruning saw.
Here’s how we handle that: Remove the PTO shaft between the PTO and gearbox. With a little up force on the 3 point hitch, use a big pipe wrench to unscrew the auger. It screwed in, it’ll screw out. Be nice if tractors had a reverse on the PTO.
Some folks I know buy hydraulic post hole augers for the reason that they can reverse.