Need to remove rock tops............

[harpoonalt]

I put in a fire pit a few years ago and surrounded it with pea stone. Now I've decided to change the surround to some sort of flagstone. However, to do this, I need to remove the tops of 3 rocks that stick up slightly into the patio area. The rocks are part of much larger rocks below. I got a quote from a landscape company for $2000 for the job and they were going to take a saw to the rocks and top them that way. Is that the best way to get rid of them? I intend to do the job myself as the materials are about $400 and my labor.
Over the years I've sledgehammered those rocks that stick up out of the ground and cause mowing problems but I'm about sledgehammered out

 

[greasemonkeyok]

Get a rock mason to show you how to use a cold chisel to cut rocks. A skilled rock mason can cut the tops off with a few well-placed whacks. Basically it has to do with rocks having no tensile strength, and creating micro cracks that line up. Then one whack with the sledge and the top comes off.

When you see it done, it may look like magic, but it isn't. The problem with a sledge is that the force is spread out over the entire face of the sledge. With a cold chisel, all of the force is concentrated along one short line.

 

[forgeblast]

Do you have a picture of them. You could get a diamond blade and cut them down and then put the pea gravel over them, drill holes and use feathers and wedges, or rent an electric jackhammer.

 

[harpoonalt]

Only picture I have at the moment is from when it was first built. You can see 2 of the rocks poking up through the stone. The landscape guy was going to saw grooves in the rock and then sledge the tops off. I need to drop them down about 6 inches to allow for sand and the stone. Maybe less if I raise the stone a few inches. I'm assuming they intend to use one of those gas powered saws with a diamond blade. Never used one but not afraid to try.

I've sledgehammered quite a few in my yard to make for easier mowing but it's time consuming and quite a workout.

 

[Baby Grand]

Looks like glacial cobbles & boulders. As a paperboy I watched with great interest one sunny day as my favoite customer, Mr Macnamara, removed the top of a big piece of "ledge" that was cresting out of his lawn. Tom was about 70 years old and about 5' 3" and always wore a tie and nice shoes. He used the Roman method:
First he dug a ditch about 12" deep all around the rock.
Then he built a large wood fire in the trench and over the top of the rock.
After the fire had burned for about 6 hours (about the time I arived to collect my money), he dumped a large trash bin full of cold water on the fire. The rock split up into large pieces, which he carted off to the old stone wall on the edge of his property.

 

[Dr_Zinj]

/laugh

Babygrand, that's exactly how I've removed some boulders on my property pre-tractor. And how I'd break up some that are too big for it even now.

 

[forgeblast]

You could get a diamond blade for an angle grinder or even a circular saw. Just groove it and smash it and then groove again.
just put the grooves 1/4'' apart and it will clean up well. I would get a masonary chisel to help with knocking the grooves apart.

 

[tractchores]

You might try the wedge and feather method. Basically you drill holes and use the wedge and feathers (metal shims) and tap them in and they create a crack and 'cut' a section of the rock off. The hardest part is the drilling, but it works pretty good for small rocks. I've found it doesn't work so good when you're trying to cut through big / deep sections of rock (need bigger wedges and drills for that). Search on youtube for some videos of wedge and feather to get an idea.

 

[Iplayfarmer]

If you have a Harbor Freight near you, go get their hammer drill... Rotary Hammer - Save on this 3-in-1 SDS Rotary Hammer

You can get it for $64 after a 20% coupon. It comes with a chisel that will work to nibble away the rock. I used mine to dig a 12" diameter hole in 60+ year old concrete that was full of medium sized rocks. I was amazed at how well it works.

 

[davedj1]

large blow torch and Ice cold water, they will crack to pieces. Just wear eye protection and your cup!:confused2: