I need to remove a small asphalt pad (approx. 5′ x 6′, maybe 6″ thick) and a concrete pad (approx. 2′ x 4′, not sure of thickness)
and am planning on renting an electic jackhammer from Home Depot
for this purpose. I’m guessing removal of the asphalt should be relatively straightforward but have no idea what to expect on the concrete pad (I’m guessing the pad is approx. 80 years old and contains stone agregate). I’ve never used a jackhammer before and wondering if anyone could provide me with any tips on using it.
Thanks in advance,
Ron R
Replies
I used one once to break up a sidewalk, and got along pretty well. the only big problem that I can remember was that it was heavy, and the work was tiring.
I started out with a pointed tool on the machine - Kind shaped like a center punch. Didn't take long to find out that it would wedge itself in place if it couldn't break through the concrete where I set it and was hell to get out. Once I switched to one with a wider blade, I didn't have any trouble.
Use hearing and eye protection. And maybe a dust mask. And invite a big burly friend over to help.........
Redneck Extraordinaire
Thanks for the feedback Boss.... I believe the rental comes with a few different tips; I'll start out with the wider one on the concrete.
80-year old concrete can be very hard. Hopefully it has NOT aged gracefully. I've used hte 120-volt rental electric jackhammers a number of times. Get both the point and the chisel, about 2-3 inches across. The wide chisel (like 5-6") only works on frozen ground, hard-packed soil or on a bigger jackhammer.
The electric ones are okay for 3-4" of asphalt or concrete. If the asphalt is really 6" thick, hopefully it was done in two layers that will split apart when hammered on. 3-4" concrete goes fine, the problems arise with 1) curbs and 2) rebar or WWF. Curbs take so long to beat art with a small jack hammer, you end you throwing out your back trying to toss the whole thing in the truck. With stell, you've got to hammer at it for a long time to get enough space to get a torch or sawzall or bolt-cutters in there.
Remember that Farside cartoon about "Jackhammer Training School" with all the (large) students being urged by the instructor to "Let your belly do the work" as they hang their "spare tire" over the jackhammer?
Thanks for the information David. The concrete pad I mentioned I believe is somewhere around 6" to 10" thick (maybe better described as a concrete block!); stairs from a rear porch on the house used to run to it. As you said, I'm just hoping the concrete breaks apart fairly easily.
And I do remember the Far Side you speak of; I wonder what Gary Larson is up to? I really enjoyed that comic strip.
Ron
It is unusual to have a pad 6 to 10" thick although that could be a likely thickness of a footing around the perimeter. Sounds like you're in the market to rent a pneumatic jack hammer and a trailerable air compressor. You need about 100 cfm so your shop compressor won't cut it. Those are readily available at serious (versus suburbian) rental yards but are more work to use and more $$.
Whereas if concrete block was used and filled with concrete, you may well be able to break that up with an electric jackhammer.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
I'm hoping it's the thickness of the footings around the perimeter only, as you mentioned. I'll check on it tomorrow evening, something it sounds like I should do before renting the electric jackhammer... ;-)
Thanks,
Ron
I rented an electric jackhammer made by Bosch to break up a 12x16 concrete patio 4-6" thick in the center and about a foot thick on the edges. Whatever you do, get a thicky padded pair of gloves, good goggles, and ear plugs.
Use your strength to only help guide and steady the jackhammer.
In the beginning I made the stupid mistake of trying to manhandle the beast by gripping hard on it and bearing down. A light touch makes the jackhammer do most of the work.
A long pry-bar is an essential tool to help nudge away large pieces as the jackhammer creates fractures.
Also, a large sledgehammer can do the job faster on some slabs, also with the help of a pry bar. Ear plugs and goggles are especially important here.
The noise made when the sledgehammer lands on the pad can do a number on the eardrums.
Ron, We use our electric jackhammer for excatly what you are describing. It works very well. It feels like your going slow to begin with but once you break through it gets easier. The advice on using your belly is good it is excatly how we do it. Even on thick concrete slabs it will work just go for smaller pieces. If you run into reinforcing wire in the con it will be tougher going. It also would not be good on thick con like footers. One tip use a heavy gauge cord. Good Luck.
What was that concrete used for originally? 6" to 10" thick overall is quite unlikely for flat work from 1922. Concrete was hand mixed on site back then, and at least here, the ingredients were delivered by mule drawn wagons. They generally used as little of it as they could. Also, rebar is very unlikely for residential work from 1922. It sounds like it may have been a step or a porch, which usually was just 2" - 4" thick over rubble fill. Those break up easily and inexpensively with a sledge.
Even if this thing really is a full 10" thick, it only weighs about 900 pounds, so you should be able to dig out and get a lever under it. Lift one end and get some blocks under it, so it no longer has good support from the ground. Then whack it with a sledge. There's a good chance that that'll break it up, and you'll save the rental on the electric hammer. It's hardly worth schlepping out to the rental place twice for such a small job.
Ditto, of course, on eye protection, gloves, and such. Also, are there any windows nearby? If so, protect them from flying chips.
-- J.S.
Edited 5/1/2002 10:16:49 PM ET by JOHN_SPRUNG
The thick slab tells me that it was done by amatures who probably used overkill to satisfy their urges and needs. That means they probably used an excessive amt of Portland which made it very hard but also somewhat more than average brittle.
I own a bosch 67# Brute and have used it not only for concrete but for lege removal also. (I'll post those pictures if Prospero ever quits rationing our digital allowance.)
Always have at least two bits on hand. If you stick one solid yuou can release it and use the other to open the rock around it.
Keep your bits ground sharp. I keep a hand held 4.5" grinder on the job with a bucket of water for cooling. A sharp bit can cut twice as fsssst as a blunted one. Get yourself into something hard and you can turn the steel red hot and wear your self out.
Let the hammer do the work. You are there to aim it and stop it from jumping away. Rock it gently back and forth with your hips or body weight. If you force on it you'll have the same kind of arthritis I do - the painful kind! By rocking it a little, you make a biggggger hole with the bullprick and are less likely to get it stuck tight. Just remeber, you're slow dancing your baby tonight, mnot packing it in tight. If it is hard stuff, don't try to kill yourself with one hole. Move over fopur inches and drill a line. It will fracture there eventually. Keep you eyes out for steel inside too and move over again.
The extension cord should be a #10. If you are renting they will likely rent you one because extended use of this unit on a cheap cord will fry their motor.
They also have spade bits for the asphalt or digging in frost or hardpan. Normal for concrete and rock would be the poijted bullprick and the chisle points.
With patience, you can do the same job as with a 90# hammer and air but not quite as fast. The Brute is lighter but has a higher BPM rate. Leaning on it makes it heavier but hurts your body. The heavy or padded gloves is also a good thing. They keep the vibrations from traveling to your cartilage. the handles are energy absorbing on this hammer too.
Now go forth and conquer.
Excellence is its own reward!
Piffin-
I've used the Brute extensively and my experience is EXACTLY as you described. If there isn't a lot of area to do but the concrete is thick or bulky, I just stick with the ol' Brute and chip away along the edges.........When there's a lot of thick crap to demo, you're right, the Brute would take forever and just kill you in the process. Then it's time for the 90# and the tow-behind! In that situation, compared to the Brute, the 90# is ALMOST a pleasure.
Ken Hill
ALMOST!Excellence is its own reward!
Thanks alot to all of you for the information. Assuming that weather holds up for this weekend, I should have something to report early next week.
Ron Rappel
I own a Bosch electric and like it a lot. It's perfect for what you want.
Thanks for your feedback Gunner...
Ron
The piece of concrete I'm talking about John I believe was to support a stairway that ran from an old porch down to the ground (not sure that the correct term is "pad"). I'm hoping you're right about only a few inches thick with rubble fill...
Ron
For reference.
I used an electric jackhammer to remove part of a foundation. A piece 12"x2'x8'. It too most of 4 hours to reduce the concrete to fist size and smaller.
I would consider a manual approach. Asphalt usually yields to a good digging bar. Dig out an edge to give the pieces a place to go and attack the slab with a chopping motion. Try for narrow pieces about 2" wide. I have had luck with mattocks and axes on thinner or softer asphalt.
The concrete is handled a little differently. Dig out an edge and then undercut the slab. Undercut just a few inches deeper than the slab leaving about 10" suspended. grab your favorite sledgehammer, you do have a favorite sledgehammer don't you, and whack the slab at the suspended edge. If you have been praying to the right deity and eating your Wheaties the slab will graciously snap near where it is still supported. If the slab is reinforced, likely, a pair of bolt cutters should take care of the 9 wire. If it is rebar a oxyacetylene torch would be my choice for cutting it. With such a small pad I might try to dig out all sides and keep whacking. At 2 by 4 feet any rebar should break free without being cut.
I'm not sure that the electric jackhammer wouldn't involve about as much grunting as the manual method. I have used both methods and for a small slab I save the rental costs and get aerobic with it.
My favorite sledgehammer is named old man Bosch
Excellence is its own reward!
Well, rented the jackhammer (Bosch's "The Brute") from my local Home Dept Saturday. As suggested, used the 3" or so wide chisel bit for going through the cement and asphalt.
First, the good news. The jackhammer sliced through the asphalt like butter! As for the cement pad, it was a little more work, but still relatively easy. Sure glad I had the hearing and eye protection! The pad was a little over a foot thick, but there were a number of large rocks, bricks, and a couple of old cement pillars buried inside there which made the work go quickly. I found the hardest part of using the tool was having to move it from the section I just demolished to the next section to work on. Can't imagine what it would have been like doing this by hand with a sledge hammer!
Now, the bad news. After going through the asphalt, I found large crushed stone underneath it. After shovelling that away, I found another layer of concrete! Broke through that, and there was a layer of wooden planks. Below that, a number of pieces of 1" thick slate. Finally, the next layer was asphalt again! I believe that there's just plain earth under that, but by this time I was not only sore but the 4 hours was up on the rental so I decided the remainder of the demolition would have to wait for another weekend.
No idea why all these layers! I guess it's easier to bury something than it is to haul it away.
Thank's again for all the suggestions.
Ron
When you haul it away, you'll discover the landfill prices that brought on that decision to backfill your drive with it.
BTW the 3" is a spade bit as is the 6" A chisle bit is only the same width as the shaft, shaped flat instead of pointed like the bullprick. The chisle point starts easier than the wider spade bit. You are right on about the hearing protection.
Rental yards here for most items five hours is same as a day and four days same as a week. and if you rent for a day where they aren't open sunday to return it you get a free day.
Glad it came out ok for you. Now you are a real man! <pat on back> Did mama sleep good that night?
Excellence is its own reward!