Foo - Big Rock Breaking--Easily?

Hubby and I are in the process of digging 4 four-foot deep holes to support our new patio.

In the bottom of the first is a large rock, which when removed will deepen this pit to 4 ft. plus. The dang thing is big and heavy but if it were in smaller pieces we could get it out pretty easily. First my husband tried breaking it with a sledge; no go. Then he borrowed a jackhammer (electric) which drilled a nice 2 inch deep hole in it--without a crack. He tried sledging it again and it is still whole. We are in the process of attempting to use a looooong lever and hoisting it out, but we will have no way of swiveling it to the side of the hole (the hole is about 2 ft. x 2 ft. wide).

We are at an impasse here. We don't have access to any explosives, and don't have a backhoe or engine hoist. I suggested that we try thermal shock: build a small charcoal fire over the jackhammer hole, let it get real hot for a while then pour cold water over the hot spot.

Oh, the rock seems to be granite like most of the rocks around here.

Any other ideas?

Hubby and I are in the process of digging 4 four-foot deep holes to support our new patio.


And why do we need these holes--we're a buildin' it to code, permitted and everything and our city requires everything way over engineered (according to our architect!)

Use the chisel bit for a jackhammer not the "donkeydick." Or you culd always keep digging to get around the entire circumference of the rock then go under it to get a chain around it. Explosives would be cool but your neighbors may call the cops. Worse case senario is the Dept. of Homeland Security would show up with the BATF and call you terrorists.

Keep using the chisel bit of the jackhammer.Start about 2" to 3" from the edge of the rock and repeat over and over.It will take some time.Just don't drill right in to the center of it that is useless.

Thanks for the suggestions on jackhammer use--and for the new terminology. "Donkey dick" is a good name for the tip my husband had been using.

Right now my husband's got two of our kids out there and they are swinging a really big beam in place to attempt some leverage from both sides. If he gets this dang thing out of the hole, he'll be a hero, but if he crushes something on his body, I'll kill him!

Explosives would be nice, fun too. We could make a party of it--come watch the neighbors blow up their house. . .!

Back in the old days, a hole about 1.5 cm round would be drilled into the rock with a hand bit and a wood wedge would be hammered into the hole in order to crack the rock. Also adding water to the wedge may cause it to expand and crack the rock. A number of holes would make this method work, so if you have a powerful hammer drill with a concrete bit it may work.

Another method would be to find a few burly guys, a box of beer, a chain/cable and a truck.

Back in the old days, a hole about 1.5 cm round would be drilled into the rock with a hand bit and a wood wedge would be hammered into the hole in order to crack the rock. Also adding water to the wedge may cause it to expand and crack the rock. A number of holes would make this method work, so if you have a powerful hammer drill with a concrete bit it may work.

Another method would be to find a few burly guys, a box of beer, a chain/cable and a truck.

We got the rock out of the hole. My oldest daughter and I worked the lever, and my husband and son were the ones to stack the wood for the support scaffold and re-rig the chain when necessare. It's amazing at how small the rock is, rather heart shaped, it doesn't look all that much larger than two 50lb sacks of feed. The thing has to be dense.

I had thought of the wedge trick too, but it took so long for my husband to drill the holes in the rock with the jackhammer, that I thought it would be a bust to try it. Maybe on the next rock in one of the 3 holes that are left to dig?

As for burly guys and the beer--we have the beer, and probably could borrow the truck, but all the guys we know aren't all that burly. And no back yard access for the truck--we can't even fit my husband's bug in!

Thanks!

it doesn't look all that much larger than two 50lb sacks of feed. The thing has to be dense.

Hmmmmm, must be made of rock :rolleyes: :D

Hmmmmm, must be made of rock :rolleyes: :D

Smart@ss! ;)

Of course there is fluffy, light lava rock, crumbly sandstone, and then there is this stuff.

Dense like reeeeely dense rock, ya know? :p

It takes a lot more than just the weight to get it started. I'm not sure if it's adhesion to the mud or vapor lock or both, but they're darn hard to break free when they've been buried for a while.

If it were me, I'd say screw the code, this bad boy would make a pretty good foundation for the posts.

It takes a lot more than just the weight to get it started. I'm not sure if it's adhesion to the mud or vapor lock or both, but they're darn hard to break free when they've been buried for a while.

If it were me, I'd say screw the code, this bad boy would make a pretty good foundation for the posts.

We didn't have any vapor lock or mud; we have very good drainage at our house.

I think the thing would've made a pretty good foundation too, but the dang buiding people from the city have to come and inspect the hole befor we start!

If you can dig around the hole, you can try to build an "A-Frame", better if you know a welder who can simply weld 2 pieces of metal together with a cross beam for rigidity. Then you can use chain or real strong rope and try to use the A-frame to get the rock out of the ground. Maybe if somebody has a 4x4 with a hitch or a winch would be useful.

I like the explosives idea too but probably not a good idea in this day and age. :)

Jay