property has lava-rock in excess. How does one put in fence posts?

[BuildBliss]

As the title says, my property has lava-rock in excess. How does one put in fence posts? I attempted to drive the steel T-posts and the ground just laughed.

I would happily rent a bobcat and auger to dig the posts if I was more confident that the auger would succeed. Do I need a hydraulic breaker? Yikes...

At some point I have to get a septic system in this hard stuff. Can a vehicle as small as a larger bobcat rip the lava-rock-filled ground here or is this a task for a much bigger machine like a dozer with a ripping attachment?

[Thronester]

I had success with a big SDS MAX rotohammer/rock drill and an 1-3/8”x18” drill bit. I would drill down about 12-16” depending on the topography and slam them in with a post driver by hand. Some times the rock would break up or the t post would pull out so I sprinkled dry cement around the post and it was nice and sturdy by the next morning. Not sure where you are but this was in lower HPP and all blue rock.
HARD work but it saved me quite a bit of money. Otherwise I couldn’t afford to do it.

As for septic an excavator with a big hammer will do the trick. Septic install must be done by a licensed contractor. I used excavationtech. Stanley did a great job
Hope that helps.
Aloha

[BuildBliss]

Thanks for sharing your experience and making a septic installer recommendation, Thronester.

I like the powdered cement idea. 

I don't have a flat crust of lava (and to be honest I'm not in Puna, I'm in LZ4 on the Kona side) but instead its small rock and chunks 6-15" in aspect over a hard subsurface with minimal soil holding it all together. And its on a 2.5/1 slope.

I am curious about how much of the septic job can be done by me. I'll have a bobcat w/backhoe attachment and could at lease get the hole and leach line trenching dug. I suppose the sceptic installer would have to agree to the help/money saving step.

[MarkP]

I posted this in another past thread:

"If you have solid rock at the surface, that's the best situation. Rent a hammer drill and a 1 1/2" bit, drill a hole about 12" deep, hammer in T-post. Repeat."

1 3/8" is the better size but 1 1/2" works too.

As for the septic system a contractor is required for it to be legal. They will have their own equipment. Mine used an excavator with jackhammer and bucket attachments, switching back and forth as needed.

[calsr1991]

I posted this in another past thread:

"If you have solid rock at the surface, that's the best situation. Rent a hammer drill and a 1 1/2" bit, drill a hole about 12" deep, hammer in T-post. Repeat."

1 3/8" is the better size but 1 1/2" works too.

As for the septic system a contractor is required for it to be legal.  They will have their own equipment.  Mine used an excavator with jackhammer and bucket attachments, switching back and forth as needed.

Can they install the septic system with no house plan or permit? Or is the house permit required?

[MarkP]

I had a house permit, since expired. The house project is not dead, just delayed.

[BuildBliss]

I had a house permit, since expired.  The house project is not dead, just delayed.

Common and frustrating story, it seems. I feel your pain. Have you a need to resubmit electronically now?