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Langning
Premium
join:2003-04-28
Marlborough, MA

How can I break a rock?

I am building a retaining wall with concrete blocks and toward the end of wall I hit a rock (about 8 inch too tall). I was hammering and prying it and was able to crack some corner/edge pieces. Just curious of what you guys use to break rock short of hiring landscape people or heavy equipment.

My original plan was to end the wall at the rock but my wife likes to see the wall a few more feet longer. Could I use corded power drill (what type & size of drill bits) or some type of hammering drill/jack hammer?

I am just looking for easier and inexpensive way. Preferably hand/power tools I can pick up from Lowes/Home Depot.




tcope
Premium
join:2003-05-07
Sandy, UT
kudos:2

1 recommendation

What about making a mold and pouring some cement on the rock so that you can stack the retaining wall blocks on top of it?


rawgerz
The hell was that?
Premium
join:2004-10-03
Grove City, PA
reply to Langning
Heavy equipment or maybe a jackhammer.


DataDoc
My avatar looks like me, if I was 2D.
Premium
join:2000-05-14
Martinsburg, WV
reply to Langning
Get a bigger hammer.


seaquake
Premium,MVM
join:2001-03-23
Millersville, MD
reply to Langning
Tell your wife if she wants it longer that she needs to go out and break up the rock.

Best bang for your buck will be renting a jackhammer. It may be pricey but should save you a lot of time in the long run. Using a hand-drill, even a hammer drill, will take a long time and won't be fun.


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3

1 edit
said by seaquake:

Best bang for your buck will be renting a jackhammer. It may be pricey but should save you a lot of time in the long run. Using a hand-drill, even a hammer drill, will take a long time and won't be fun.
Not too pricey considering if run properly it does most of the work. Do be sure to rent an electric unit which the rental place may call a chipping hammer if you get a pneumatic jackhammer you will need to rent and tow a rather large air compressor to the job and back. Don't forget a few dust masks and safety glasses.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician.


bryank

join:2000-03-23
Plainfield, IL
reply to Langning
Not sure if this will work, or how long it will take... But drill a series of 1/2" holes (or larger) with your corded hammer drill and a masonry bit. Then take a steel wedge spike and insert in the holes and hammer them down. Should split the rock in half. The only thing is you kinda need to know how deep the rock is buried.

But I would go the jack hammer route, I think that would be fun.


Greg_Z
Premium
join:2001-08-08
Springfield, IL
reply to Langning
The best solution, is to use the rock to your advantage. You will though have to secure the wall on top of the rock with silcon adhesive, but use it as part of the design. Otherwise, get a jack hammer and go to town.
--
I threw out the map a long time ago. Now I follow my own direction!


ttiiggy
Premium
join:2001-03-27
Bozeman, MT
reply to Langning
I would go with the hammer drill. Draw a line an extra inch wider than your desired block placement. Drill a line of ~1/4 holes a couple of inches apart. Bash it a bunch with your biggest hammer.

»www.youtube.com/watch?v=VLjXwJyaOTI

»www.youtube.com/watch?v=gKai9nfHO-M

»www.youtube.com/watch?v=FtQRCBl7pEM

--
If it ain't broke, you haven't tried enough stuff yet.


beck
Premium,MVM
join:2002-01-29
On The Road
kudos:1
Reviews:
·Stablehost.com
reply to Langning
I'm a girl and I agree. Tell your wife to break up the rock if she wants the wall longer.

Otherwise, build up to the rock and use it as part of the wall and finish your wall on the other side.

Or find some type of statue thing to put on top of the rock that she likes and build up to that.
--
Some days it seems like ALL my brain cells have died.


61999674
Gotta Do What Ya Gotta Do
Premium
join:2000-09-02
Here
kudos:1
reply to Langning
Some type of hammer drill or jackhammer are your only options, getting rid of the whole rock would be better but close to impossible unless you plan on spending big money.

There was an episode on This Old House(I believe) about a problem similar to yours but they were dealing with the foundation for an addition, the more they dug the bigger the rock got , if I remember right their plans were to remove the rock until they found how large it was and ended up jackhammering enough out.
--
What was I in Highschool ?
A Ghost.


PageTurner
Premium
join:2004-08-16
US
reply to Langning
You've done a nice job, the wall is great.

I do think you deserve to buy one of those drills in UT #3.And after all, you will probably use it on future projects.

If push comes to shove, you could frame the bottom in and pour concrete in it, to make your bottom layer. Then build up with your blocks. The color should be close and you could apply some crete to make a roughed up apearance to it after it drys.

You could then put a nice veranda box (long narrow planter) in front of it. Nobody could tell it is different behind it.

You have to be pretty strong to handle a jack hammer.

misfitx7
Premium
join:2007-06-04
Centerville, MA
reply to Langning
I have done this before, and have tried both routes. Depending on the density of the rock, the jack hammer may be really tough. I had some rocks that just would break with the jack hammer. If you try the jack hammer, let the machine do the work by just holding it in place. Drilling holes on the line that you want to break it and pounding wedges into those holes is your best bet, this is what a mason would do. I was lucky and was able to borrow a masons wedges. you want every hold to have a wedge and then you will have to move down the line pounding each one in a little at a time. Good luck


jjoshua
Premium
join:2001-06-01
Scotch Plains, NJ
kudos:3
reply to Langning
What are you using for base material?

Also, the second shot shows that the wall isn't exactly straight. Perhaps it's some camera lens distortion. You might want to set up a string line to keep you on track.

Langning
Premium
join:2003-04-28
Marlborough, MA
reply to tcope
said by tcope:

What about making a mold and pouring some cement on the rock so that you can stack the retaining wall blocks on top of it?
I did just that on another rock that was just 2" too tall (less than 6" from ground as I am burying the 1st course and my blocks are 6" in height). I spent 1 full day dug around and under the rock while hoping I could pry it out. The rock goes into the hill and I finally gave up and opted the concrete approach. Between hauling 10 80lb concrete in 2 trips and mixing them in a wheelbarrow with a shovel, it was the hardest part of my project.

The 2nd rock is 3" above ground level. If I was to pour concrete, I had to make the base 12" tall. Unlike above after I backfill with crush stone/gravel, no one will see the concrete/bottom course.


This picture should give everyone some perspective of why my wife wants to extend the wall.

I worked on the rock yesterday afternoon with more chiseling and hammering. It did cracked on the inside and I was able to lift it perhaps 2" with my 6-foot prybar. The rock is about 3'x2'x20" in size. I tried to hammer it to reduce its size/weight so that I can put it on my hand truck. It is still too heavy and too big (I am a small guy). My new strategy is to dig 3 feet deep hole in front of the rock and move it out of the way first.

Langning
Premium
join:2003-04-28
Marlborough, MA
reply to jjoshua
said by jjoshua:

What are you using for base material?

Also, the second shot shows that the wall isn't exactly straight. Perhaps it's some camera lens distortion. You might want to set up a string line to keep you on track.
3/4" crush stone underneath and behind the wall. I was supposed to use "crush run" (mixture of stone dust, gravel, and stone) for the base and crush stone behind the wall. My house is built on a rock hill and the area is the end and side of my driveway which previously retained with 6x6 landscape timbers. What I have removed so far are rocks and fills the builder put in. Since my wall is only 24"+6"(buried)+3"(cap) and the soil drains well and compacted, my trench is only 9" deep. I put about 3" of crush stone (tamed again) and will bury the 1st course... Behind the wall, it is about 6" to 12" of gap filled with crush stone wrapped in landscape fabric.

You are right, the wall isn't straight. My problem was I lined up the front of my base course. The block manufacturer molds 2 blocks together and splits it afterward to give the distinctive appearance; their sizes therefore aren't exact. Plus I used 3/4 crush stone as base material, the base course isn't exactly level either. The instruction calls for 1/2" of sand for easy leveling; I hated the idea of having sand underneath a gravity wall that can move. After filling in the gap and back filled the back with crush stone, I gave my best effort. If standing in front of the wall, the wall looks better.

averagedude

join:2002-01-30
San Diego, CA
reply to Langning
Google expanding rock breaking.
Short story; drill hole, pour in mixture, mixture expands and cracks rocks, remove smaller pieces.


RevMortis
I Hear Dead Silicon
Premium
join:2005-05-10
Saint Paul, MN
reply to Langning
I know a guy up here in MN that does landscaping as a part of his Garden center/greenhouse business. You can "sell" him large boulders and he'll come out and excavate them for you. He then turns around polishes it and sells it to some other person as a hardscape feature.

Might check with landscaping people in your area. I bet they can get it all out in one piece!


Jon
Premium
join:2001-01-20
Lisle, IL

1 edit
said by RevMortis:

I know a guy up here in MN that does landscaping as a part of his Garden center/greenhouse business. You can "sell" him large boulders and he'll come out and excavate them for you. He then turns around polishes it and sells it to some other person as a hardscape feature.

Might check with landscaping people in your area. I bet they can get it all out in one piece!
That's a good idea. I'd call a few and check.
Not sure what kind it is but a rock that size sells for about $500 to $600 at the stone yard by me.
Even if they don't give you much. You get it removed and a few bucks too


rawgerz
The hell was that?
Premium
join:2004-10-03
Grove City, PA
said by Jon:

Not sure what kind it is but a rock that size sells for about $500 to $600 at the stone yard by me.
Wow, whats sandstone go for?
--

You can't make all the people happy all of the time. But it should be common sense to shoot for the majority.


Jon
Premium
join:2001-01-20
Lisle, IL

2 edits
Not sure, Like I said depending on what type it is...
Still, Rocks are not cheap. At least around hear. I probably easily spent $1000 on various stone when I put in my pond last year.

Plain old Cobbles go anywhere from 11 to 25 cents per pound. The big boulders though I don't think they sell by weight but I'm not sure. The boulders I looked at while planning, ranged from 300 to 900 dollars.


61999674
Gotta Do What Ya Gotta Do
Premium
join:2000-09-02
Here
kudos:1
reply to RevMortis
said by RevMortis:

Might check with landscaping people in your area. I bet they can get it all out in one piece!
Well maybe not, the "rock" in question may be a small corner of a very large one.
--
What was I in Highschool ?
A Ghost.


whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
kudos:9
reply to Langning
You can use a 'pike' and a sledgehammer, if you don't want to rent a jackhammer. Your wife holds the pike while you smash it with the sledgehammer. (She may quickly change her mind.) It is back-braking, tedious work - but it will get the job done the old-fashioned way.


Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand
said by whizkid3:

You can use a 'pike' and a sledgehammer, if you don't want to rent a jackhammer. Your wife holds the pike while you smash it with the sledgehammer. (She may quickly change her mind.) It is back-braking, tedious work - but it will get the job done the old-fashioned way.

In one of my past lives, I worked for the US Forest Service where dynamite was readily available.


--
. . . still recovering from brain damage . . .


whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
kudos:9
said by Coma:

In one of my past lives, I worked for the US Forest Service where dynamite was readily available.
Also old-fashioned. The OP is advised to try it if he can.

Kearnstd
Space Elf
Premium
join:2002-01-22
Mullica Hill, NJ
kudos:1
reply to Langning
im sure the neighbors would just love the guy next door playing with explosives. well just dont buy any made by Acme.
--
[65 Arcanist]Filan(High Elf) Zone: Broadband Reports


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS

1 recommendation

reply to whizkid3
said by whizkid3:

You can use a 'pike' and a sledgehammer, if you don't want to rent a jackhammer. Your wife holds the pike while you smash it with the sledgehammer. (She may quickly change her mind.) It is back-braking, tedious work - but it will get the job done the old-fashioned way.
Reminds me of the old joke, "when I nod my head you hit it"
--
"Information is not knowledge. Knowledge is not wisdom. Wisdom is not truth. Truth is not beauty. Beauty is not love. Love is not music. Music is THE BEST" - Frank Z


RevMortis
I Hear Dead Silicon
Premium
join:2005-05-10
Saint Paul, MN
reply to 61999674
said by 61999674:

Well maybe not, the "rock" in question may be a small corner of a very large one.
Even so, they might have the equipment to get it out of there in sellable chunks?!?

Langning
Premium
join:2003-04-28
Marlborough, MA
reply to 61999674
said by 61999674:

Well maybe not, the "rock" in question may be a small corner of a very large one.
The "rock" in question is the piece in the path of wall where it ends now. The dimension is about 3 feet (long) x 2 feet (wide) x 18 to 20" (high). I already broke it loose from the hill and "moved" it a couple inches now.

I researched and have doubt if electric jackhammer is powerful enough to break this rock. I may try drill/wedge approach this weekend. If I can't break it, how many pounds do you guys think a rock of this size may weight? I am thinking getting a flat dolly and somehow place the rock on it and wheel it to my front yard.



Being working alone and no extra help, I moved onto my next item and did 80% of my basement door wall/steps. Here is my work-in-progress for my last 2 days. Meanwhile, back to my regular day job...

Before:

After:


Jon
Premium
join:2001-01-20
Lisle, IL

2 edits
said by Langning:

how many pounds do you guys think a rock of this size may weight?
I'd bet thing has got to easily be 500 or 600+ Lbs.
I took some (3) large rocks from my brothers backyard a few years back that he wanted to get rid of. We ended up renting a engine hoist to get them in and out of the truck.

It's hard to tell but I think they were slightly smaller than that one. It took four of us to wrestle them into place and was still a struggle. An engine hoist might be an option for you if you have a flat spot to put it on.