Pole Barn Addition and Big Rocks

[sbarshie]

I started clearing out the spot where I'm adding onto my exisiting 30' x 30' pole barn. The issue I have is rocks, big ones that are everywhere. They range from in sizes up to 10' but they are all moveable with the right size machine.
My question is I need a building permit and not just a zoning permit since I'm making the total under roof area greater then 1,000 sqft. In my area of Eastern PA anything over 1,000 sqft needs full inspections.

I'll be adding onto the existing building with a 24' x 16' addition that requires 6 poles.
Does anyone in big rock country have experience using an excavator to dig post holes down to the required 48" depth removing all the rocks and back filling/compacting the around the hole?
A post hole digger just doesn't work here. The post hole may end up being 4' x 4' in order to remove the rocks that are direcly below post location.

There two fine examples in the attache pic of what I'm dealing with.
Any thoughts?

 

[rieferman]

On a build that we were doing a few years ago, we hit solid rock about 10 feet across. We were able to submit engineered drawings showing how we would anchor to the rock rather than removing it. In that case, the surrounding ground would be better off left undisturbed, so it was approved. Turned out great and saved a lot of time and money.

 

[sbarshie]

rieferman-I used to drive right past your place on my way to Pfizer, small world..

All of this rock can be moved, its an old glacier rock dump area Green Lane, PA, kind of neat from a geologic aspect. I just can't drill post holes.

I'm looking for alternatives to drilling since the holes will have disturbed soil on all sides.

The easy thing to do would be to fill them with concrete but apparently that's bad for rot.

 

[theoldwizard1]

They range from in sizes up to 10' but they are all moveable with the right size machine.

I would rent a jack hammer and make those 10 footers into some 2-4 footers !

Ledge rock, like rieferman, is a whole different story. You either pin the foundation to it or BLAST !

 

[gasaxeman]

I have a place in Norhtern WI. You can not stick a shovel in ground without hitting a granite boulder.
I built a large pole building up there and we had a huge rock the size of a VW bug right in the way of drive way.
We tried pushing with my old JD450 crawler loader but it would not budge.
What we did was dig around it with our skidsteer and expose as much of rock as possible.
Took a pile of seasoned oak firewood and built a huge fire all around it. Burned for half a day.
The Granite boulder broke into more managible pieces and we were able to move with the loader bucket.

 

[Lewisthepilgrim]

^ that's genius

 

[sbarshie]

The fire is an interesting idea, but moving the rocks won't be much of an issue with the right machine.

I'm trying to find out if you can backfill a giant hole around the poles once I get them to a sutable depth. Normally you want virgin soil around the pole sides and base. In my case it will be backfilled and I'm not sure that will fly.

 

[Cjk]

Can you let the baackfill sit for a year or 2 and let the frost help settle everything? I know it delays your project but may be necessary.

 

[ABADWILLYS]

i ran into rock doing the holes for my pole barn(normal for upstate NY), some we dug out with a excavator,.. some as big as a volkswagon also.. but i had to rent a tracked jackhammer to break some others up, i did have one hole that was on rock ledge, we ended up pinning that one pole to the ledge, my building inspector looked at it,understood the situation and signed off on it..ive had no problems with my building ..you guys building in that red dirt or clay are lucky, we have rock all over here.
..hammering away

 

[MagKarl]

I'm not a geotechnical engineer, but I don't see a difference in the size of the hole as long as it is compacted backfill. An auger is faster and gives a smaller and more predictable size hole than a backhoe/excavator, which surely helps production crews and saves money when concrete backfill is required. I'm building a pole barn this summer and plan to auger what I can, and if I hit rock switch to the backhoe. My ground is clay/rock, you just don't know what you are going to hit till you get into it.

 

[G_P]

Ahhh the joys of living in the Northeast US. Cant poke a nail in the ground without hitting a rock!

 

[MScott]

No different here in Ontario. Living on the Precambrian shield means living with rock.
As to the OP's question, I would think that thoroughly tamping the fill every few inches would work. I have never built a pole barn, but I have observed the Hydro guys installing poles and this is what they do.

 

[readhead]

Remove the rock. Backfill and compact the hole. Drill the hole for the post like you would the others.

 

[jwith68]

You might check to see if anyone in your area has a hydraulic powered rock drill on a skid steer loader. They are not common, but they are out there and can drill through solid rock or concrete. Not something you'd want to buy, but if you can hire it done, it might be fairly economical for 6 holes. Also, some utility boom/auger trucks are equipped with drills that can deal with hard rock. There's a guy in my area that has an old utility truck that can drill through about anything, and he works cheap, too.

 

[sbarshie]

This is going to be my plan, just wasn't sure if it was common.
Thanks
"Remove the rock. Backfill and compact the hole. Drill the hole for the post like you would the others."

 

[rieferman]

Green Lane eh?? Small world is right! When I was still selling construction, I sold and built a few nice buildings out that way, including major site work in both cases. PM me if you're interested in a meet up at any point, or if you want a recommendation for an excavator - my guy did a bunch of buildings for me, including the ones out in Green Lane and as my own property.

But yes, remove problems (rocks, stumps, topsoil), proper fill and proper compaction. Green Lane inspections can be picky. On our big fill job, we filled in 10" compacted lifts. They did a soil compaction test to verify.

 

[Crazy Backyard Builder]

I have a place in Norhtern WI. You can not stick a shovel in ground without hitting a granite boulder.
I built a large pole building up there and we had a huge rock the size of a VW bug right in the way of drive way.
We tried pushing with my old JD450 crawler loader but it would not budge.
What we did was dig around it with our skidsteer and expose as much of rock as possible.
Took a pile of seasoned oak firewood and built a huge fire all around it. Burned for half a day.
The Granite boulder broke into more managible pieces and we were able to move with the loader bucket.

I love stuff like this, brilliant !

 

[southernfriedcj]

This is going to be my plan, just wasn't sure if it was common.
Thanks
"Remove the rock. Backfill and compact the hole. Drill the hole for the post like you would the others."

That will work like a charm. I've built roads and houses on 40' of fill. No problem.