Digging post holes for pole barn

[Sparky88]

If you can get one from your local rental store, get a mini excavator! They are very easy to learn to use. MUCH easier to dig holes with then a bobcat with auger attachment! I have done it both ways and the mini is by far the best. Drilled holes up to 24in diameter and down to depths of 14 feet with extensions.

One other thing to think about. Concrete is fine to fill the hole up with, it won't rot. Not sure why someone would think that. But you can also fill it with 3/4-1 inch white rock (road rock), whatever you call it there where you are. The rock compacts down and acts just like concrete but at a cheaper price. Our local utility uses this method to set power poles and they are 30-40 up in the air.

For termite protection, buy some Termite Proof. Mix with water and dump in down the hole. Also spray the wood and let it soak in. Works as good as Termidor SC but at much less cost.

My two cents.

 

[rd_macgregor]

I don't want to divert the thread too much, but someone mentioned using shorter poles, then framing up. When I was researching horse barn designs, I ran across several companies that offered this sort of modular approach, with the stalls and everything already installed!
Monitor Style Modular Barn | Horse Barns | Horizon Structures
Instant barn!
BOB

 

[UncleBuck1]

If you can get one from your local rental store, get a mini excavator! They are very easy to learn to use. MUCH easier to dig holes with then a bobcat with auger attachment! I have done it both ways and the mini is by far the best. Drilled holes up to 24in diameter and down to depths of 14 feet with extensions.

I've seen the mini excavators with auger attachments, but I don't believe any of my local rental places have them.

Also, I've done a bunch of reading since last night regarding backfilling. My "new" strategy is to start as I discussed above, by nailing a horizontal brace 42" above the bottom of the post and then drop it into a 48" hole. But instead of backfilling entire hole with concrete I'm only going to pour concrete to maybe 6" above the bottom of the post (12" above bottom of hole) for the footing and then backfill with soil. I know that gravel/crushed rock is often used, but I have fairly heavy clay soil and I'm concerned that gravel will just act like a cistern and hold water instead of shedding it.

Also, I'm using .80 CCA treated posts; I'm purchasing them from a treating plant that primarily supplies posts for the offshore oil industry and for marine bulkheads, seawalls and piers. 6x6x16 posts are $38.21, 6x6x20 are $53.04 and 6x6x24 are $65.00.

 

[Dr Dave]

To get the loose soil out of the bottom of the holes, I use a large shop vac, with a 4' length of pcv pipe on the end of the hose. This is a lot quicker than a manual post hole digger, and a good job for the wife or kids.
If you have a future use for a 3 point post hole digger, consider the cost of renting and deduct from the price of purchase, how many times you may need to rent. Some times owning is cheaper and also more convenient. Once you have one you will find many uses, planting trees is fast and east with a post hole digger.

Dave

 

[QRTRHRS]

I've seen the mini excavators with auger attachments, but I don't believe any of my local rental places have them.

Also, I've done a bunch of reading since last night regarding backfilling. My "new" strategy is to start as I discussed above, by nailing a horizontal brace 42" above the bottom of the post and then drop it into a 48" hole. But instead of backfilling entire hole with concrete I'm only going to pour concrete to maybe 6" above the bottom of the post (12" above bottom of hole) for the footing and then backfill with soil. I know that gravel/crushed rock is often used, but I have fairly heavy clay soil and I'm concerned that gravel will just act like a cistern and hold water instead of shedding it.

Also, I'm using .80 CCA treated posts; I'm purchasing them from a treating plant that primarily supplies posts for the offshore oil industry and for marine bulkheads, seawalls and piers. 6x6x16 posts are $38.21, 6x6x20 are $53.04 and 6x6x24 are $65.00.

.80 CCA used to be the standard for post barns. I thought marine applications went to 1.00 but whatever. I do want to ask if you are going to fasten something to the posts to resist uplift? Some builders will simply cut 2x6x~12" long pieces of treated (again, treated to the same spec as the posts), drill them so that they do not split the using CCA rated screws, fasten them to the posts about six-twelve inches from the bottom. Place them on all four sides and tamp/pack the backfill around them.

If you are not sure, ask around to see what is common in your area. What with the threat of hurricanes, I would think uplift resistance would be a standard practice.

 

[QRTRHRS]

To get the loose soil out of the bottom of the holes, I use a large shop vac, with a 4' length of pcv pipe on the end of the hose. This is a lot quicker than a manual post hole digger, and a good job for the wife or kids.
If you have a future use for a 3 point post hole digger, consider the cost of renting and deduct from the price of purchase, how many times you may need to rent. Some times owning is cheaper and also more convenient. Once you have one you will find many uses, planting trees is fast and east with a post hole digger.

Dave

Shop vac is a good suggestion, especially at four feet down where a manual digger is hard to use. As for the digger, once again, it depends on soil type. The clay is so hard in some areas on my property that the three point would simply bounce on it like rock. I have had to take my electric jack hammer with a long point to break up the clay, auger or spoon some out, break up some more, auger, spoon some more... Fun stuff!

Hydraulic down pressure sometimes combined with a little forward/backward rocking to offset the drill goes a long way in hard ground. I have also done that with the 3pt. Whatever it takes sometimes.

 

[UncleBuck1]

. I do want to ask if you are going to fasten something to the posts to resist uplift? .

My land is far enough inland that hurricane force winds are not a concern, but countering uplift forces is something that I've given some thought to. My plan is to drill a pilot hole and drive a piece of rebar near the bottom of each post and pour enough concrete to cover the rebar. I will end up with a 18" concrete collar that will hopefully keep the post in the ground. Having said that, a treated wood collar is a pretty good idea too. I'm also going to put siding on the barn which should minimize uplift.