Digging post holes for pole barn

[UncleBuck1]

I'm about to start construction on a 36x48 monitor style pole barn. I had to special order the 24' poles for the center section and they're supposed to be ready for pickup in 3 weeks.

My site has been leveled and layout finalized and the next step is to drill 20 15" diameter holes for the posts. I'm planning to bury the posts 42" deep and I want to start out with 48" holes to allow for 6" of concrete under the post.

What has me stumped is whether I should buy a 3-point hitch auger or rent a skid steer with auger. A 3-point hitch auger would definately be a good investment and have other uses around my property, but I can't figure out whether it would have the ability to drill a 48" deep hole.

Can someone who's "been there/done that" give me some guidance on the right tool for this job?

 

[woodlandfarms]

I can't comment beyond what I know which is the skid steer version... 3 points generally do not have any downforce. A skidsteer does. If you have complicated soil the downforce is a good thing to have.

To get around this, you can get a hydrualic post hole digger (or build your own which is what I did), and attach it to your bucket. Then you have downforce. But it all goes to what kind of soil you are working on.

 

[AlanB]

Skidsteer auger (or dingo auger) are MUCH easier to use. not only for downforce (which is essential at times) but also for seeing what you are doing and ease of positioning.

A tractor auger is nice, but your neck and back will appreciate looking forward all day from a skidsteer or dingo.

48" is really deep. it would depend on the auger you have, but I believe most of mine are around 36" ish. you would need an extension. Generally you can dig all the way till the powerhead is at the ground surface. Measure the augers that you have available.

You will still need a manual post hole digger to get the bottoms clean. Buy the ones with the joint in the middle. You will need them to get that deep. Not to mention they are just a lot nicer in general.

 

[JimRB]

I did 12" holes for 6x6 poles using a tractor. I have a 4 foot mark on my manual post hole handles so I guess I cleaned up the holes down to 4 feet. I put gravel in the bottom of the hole and compacted it. The hope was it might drain. Probably not likely as the water table sometimes is higher than the bottom of the poles. By the way I did 38 holes. And another detail. I missed my mark on most holes so I was hand digging to get them in the correct place. Hand hoeing bags of Sakrete. It was a good way to spend a summer of weekends. I was stronger after all that digging and hoeing. No tractor to tip the 16 and 20 foot 6x6s.

 

[JimRB]

The second pole barn was just as big but we used trusses instead of 2x8 rafters so a lot less holes and I was not off my mark on the second barn. First barn was for horses. Second was for equipment.

 

[ENG18LT]

I just priced a 24" auger for my 3pt. post hole digger, $650.00. I can rent a skid steer with 24" auger for $355 including round trip delivery/pickup. No brainer there, I will be renting one. in a couple weeks as we are going to be starting a 50x40 monitor barn.

 

[CliffordK]

I just priced a 24" auger for my 3pt. post hole digger, $650.00. I can rent a skid steer with 24" auger for $355 including round trip delivery/pickup. No brainer there, I will be renting one. in a couple weeks as we are going to be starting a 50x40 monitor barn.

It all depends on what you need. A 24" diameter auger is a pretty big hole, and may only be used for things like pole barns or greenhouses. However, if you like wood fences, a smaller auger might be handy, so at least the post hold digger isn't wasted.

Are you pouring a concrete pad? Can you just add steel straps and sit the posts on top of the pad? Is the rot resistance better when sitting on a concrete pad?

 

[BeezFun]

Instead of pouring concrete under posts you can also use precast concrete pads called "pills". Standard sizes are 4" and 6" thick, with diameters 14-18". Especially nice if it's hard to get concrete to your site, and way cheaper.
If you have a lot of rocks, a 24" auger will be handy because the hole will bounce all over the place by the time you're done, and then you won't have to do any handshaving on the sides to get posts in the right location. If you're soil is rock free you might go with a 20". The bigger the hole the more backfilling you have to do.

 

[whistlepig]

About all the augers I have seen are 36" long. They do sell shaft extensions for the auger shafts. The problem that I had was that I didn't have a tractor with enough travel on the 3 point lift to go all the way to the bottom of a 48" deep hole and still be able to lift the auger high enough for the auger to clear the hole when done. I rented a skid loader with a 24" auger.

 

[SPIKER]

I would go bigger on the holes too, and use the pre-cast concrete cookies.

it is hard to get the holes aligned right and the bigger hole lets you/builder move the poles a bit not to mention getting a LONG pole into small hole can be hard.

Mark