Electric Hammer Time

March 30, 2007 8:21 AM

My wife would like to demolish two 28'l x 2.5'w x 4"d concrete sidewalk tomorrow. She went and talked to Home Depot about renting an electric jackhammer per the recommendation of a buddy who will be helping her. When talking to the tool rental guy*, he suggested that she think about a demolition hammer but in reading their site the breaker seems like a better bet. She really wants to be the one to do this and she is small framed which may be the reason for the demo hammer recommendation. I suspect that it will end up being me doing the work after she realizes how jarring it will be so her doing the work should probably not be a factor. Does anyone have any experiences that would point us to one or the other? * Tool rental guy is apparently a Hilti guy who is onsite at this home depot and the demo hammer is a Hilti too.
posted by GrumpyMonkey to home & garden (20 comments total)

I've used a Home Depot rental jackhammer. You definitely do not want to be bending over and using your arms to hold up the device in the first picture, especially over such a huge job. The chisel at the end probably weighs 20 lbs by itself.

The thing I used was more like the second picture and it still took us like half an hour to do a 2'x2'xidontknowhowmanyinchesdeep section in my basement.
posted by DU at 8:27 AM on March 30, 2007

Hilti makes good stuff. However, they draw a lot of juice - you're going to need to rent a 10 ga power cord as well.

Personally, for 4" concrete, I'd just get a big sledge and take out some aggression, but practically, I'd go with the breaker.

If you're not used to such things, though, either piece of equipment will kick your ass and make you tired.
posted by notsnot at 8:31 AM on March 30, 2007 [1 favorite]

I wanted to mention, don't break the pieces down any more than you have to - 1' x 1' chunks are small enough. The extra weight won't kill you, but the extra trips to the dumpster for smaller pieces will.
posted by notsnot at 8:46 AM on March 30, 2007

The breaker is heavier and designed so that you let the tool's weight do the work for you. You position it, and let it hammer through the slab. Reposition and repeat. With the demolition hammer, you have to put in the weight. You can make neater edges with the hammer, do fancy stuff. Which you don't need, apparently.

I'd go with the breaker.
posted by jellicle at 8:48 AM on March 30, 2007

Seconding the breaker. The demo hammer looks more like it's used for cutting holes in concrete. You want something designed to break it into carryable chunks. Some thoughts on using the breaker effectively:

1. don't try use it to cut off pieces of the slab. Use it to make a row of holes that will make the slab break when you hit it with a sledge.
   something like this
   =================
   .....x........x.........x......x
   x x x x x x x x x x x x x x
   .....x........x.........x......x
   =================
   
   where === is the edge of the sidewalk and X is a hole. (. is a placehoolder, since Mefi strips repeated spaces)
   
   After you break that series of holes, hit it a few times with a good sized sledge. pick up the pieces, rinse, repeat.
   
   
2. take frequent breaks. this thing is hard on the wrists.
   
3. break the chunks smaller than you think you'll need to. It's far easier to break the stuff than carry huge pieces.
   
4. If you're renting the tool, keep an eye on the clock. Some places charge exorbitant rates if you keep it past due.
   
   Good luck. don't plan anything for the day afterward.

posted by cosmicbandito at 8:54 AM on March 30, 2007

If your wife can drag 57 lbs around for most of the day and keep it upright, get the breaker. It's not going to be that jarring because the weight of the machine does most of the work. I think the smaller unit will actually be more jaring, because she'll have to add her own weight to it.

No matter what, make sure excellent hearing protection is used.
posted by Good Brain at 9:12 AM on March 30, 2007

A sledge hammer would do this job cheaply and it's not very hard at all. You can pretty much use the weight of the hammer to break it so it doesn't take that much strength. Oh, and it's lots of fun!
posted by advicepig at 9:17 AM on March 30, 2007

Awesome, thank you all. The breaker seems like a much better plan.

And thank for the reminder on the ear protection and frequent breaks!
posted by GrumpyMonkey at 9:18 AM on March 30, 2007

You might also consider picking up some anti-vibration/impact gloves... after about half an hour using compressed air hammers or portable gas jacks I always found my hands going numb and she may find this unsettling.
posted by prostyle at 9:21 AM on March 30, 2007

Do not get the demolition hammer. You will be at it for a week. Your back will be sore after about one hour and the joints in your hands and arms will ache and swell up.

While the electric breaker is a better bet, I would recommend an air powered jackhammer. This will cost considerably more though as you would also have to rent a compressor powerful enough to run the hammer. But you could probably finish in about two hours.

Wear safety glasses or a face shield, good gloves, and earplugs.

You could probably find a demo contractor in town that will do it for a reasonable price.

/me used to do demo.
posted by Totally Zanzibarin' Ya at 9:21 AM on March 30, 2007

For something that size, picking up the pieces is going to be the bulk of your work. Last summer I busted up an 8'x10'x8" concrete patio by hand, and breaking it into pieces was probably 10 percent of the work. Looking at the size of your job, I don't think two people are going to get it done in one day. Mine took me about three weekends (mostly alone) and I'm a medium-to-large burly man.
I've found that using a demo hammer or a breaker doesn't make it easier on you- it just makes it faster. So whether you spend an hour busting up a lot with a demo hammer or you spend three hours swinging a sledge at your own pace, you're going to be equally beaten up at the end of it. Then, you still have to pick it up and carry it away. For the price of renting the electric jackhammer you can buy the sledge outright and spread the work out over a few days.

Bottom line: If she wouldn't feel confident swinging an 8lb sledge, then she probably shouldn't be trying to do the same job, but with power tools. The tools you want are the heaviest sledge you're comfortable swinging and a Wedge Point Bar. If you have detail work to do, then you'll want a cold chisel and a 2lb hammer.

I also recommend picking up some of Arbonne's Herbal Muscle Massage, which has wintergreen and capsaicin to help the extremely sore muscles you will have the next day. Biofreeze seems to work pretty well, too, but it's mostly just menthol. If you don't do this kind of stuff often, you will be surprised at just how much work it is.
posted by leapfrog at 9:27 AM on March 30, 2007

The breaker will do the job pretty much by itself, but dragging it around will be very tiring. I'm sure she'll be capable of doing the job, but it's a good job to share with someone else.

Also, a mask for concrete dust is essential.
posted by oneirodynia at 9:29 AM on March 30, 2007

Go with the breaker, it's a little easier to work with.

Safety: Dust mask or respirator, heavy gloves, hearing protection and eye protection have all been mentioned, I'd add long pants and heavy shoes. This is not a shorts and sandals kind of job.

Motrin and a heating pad will be welcome the next morning.

Check with the rental guy, sometimes they're not open on Sunday, so if you rent on Saturday you get two days use for one days rent.

Where do you plan on dumping the waste? My garbage men won't take construction debris.
posted by Marky at 10:02 AM on March 30, 2007

We had a huge section of our sidewalk replaced and they used a sledge hammer to break it up. It went very fast. Breaking that much with a sledge would take less than an hour. Loading it into a dumpster or whatever, that might take some time but the jack hammer isn't going to help with that anyway.
posted by caddis at 10:03 AM on March 30, 2007

I doubt that some of these other posters have broken conrete before, as you are planning to do. I have.

I had some concrete slabs and footings in my backyard that I wanted to remove. I started with the sledgehammer, and probably put in about 10 hours with it, and made *decent* progress with it.

Then I discovered I could rent an electric jack hammer for $60/day. This is a real jackhammer, big, huge, and heavy. It was the best $60 I ever spent. It broke up the rest of my concretely quickly, and easily. I was expecting it to be very jarring on my body, but it wasn't. It bounces a little, but the tool itself absorbed most of the shock. Really, it was as easy an putting the thing on the concrete to break, hold the handles, and go. It was a very heavy machine, but I love it. I can't wait to rent it again someday, because it is that great.
posted by Khalad at 10:13 AM on March 30, 2007

I agree with Khalad, you should use the breaker. I have broken up lots of concrete also. It does all of the work. Hold on to it lightly and it goes right through the cement.
posted by lee at 10:41 AM on March 30, 2007

Not to be a naysayer, but I have gone through a somewhat similar thing (in the sense that there's personal and for-hire solutions) with fence pole holes. My father and I spent two days and a lot of money on rental equipment and got about 4 holes done. Badly.

We finally called someone who came out with a bobcat with an auger attachment and his rate was about $70 an hour (this would have been back in 92 or so) with a 2 hour minimum. We though "Minimum, whatever, like you're going to be done quick enough for that to matter."

They did 18 holes in 50 minutes.

My point - which I am finally getting to - is that you may want to call around and get a price to have this done. Hammer spike attachments are almost as common on those bobcats as the augers are and it may cost a lot less than you think it would.
posted by phearlez at 10:49 AM on March 30, 2007

I'm going to side with Phearlez here. I tried to do something similar, and eventually called in my general contractor, who did it in less than an afternoon, for about the cost of renting all the equipment, buying impact gloves, shields, ear protection, etc.

Seriously, for people that own the equipment, and do this kind of stuff all the time, the job you describe is about a 3 -4 hour job. They have the training, the muscle, the equipment, the liability insurance.

Pay the nice people, and let them do it. :)
posted by dejah420 at 12:16 PM on March 30, 2007

Thirding (fourthing? fifthing?) just paying someone to do everything. That's like two cubic yards of concrete, right? Ten thousand pounds or so? That job could be done in a few hours with a dump truck to remove the waste and a bobcat with a hammer attachment. It sounds like a solid week of work for two strong, large people to do it by hand.

The age of specialization is upon us - unless you really can't afford it and have to get it done I'm not sure why you wouldn't want to have a specialist with the proper tools perform backbreaking work like this.

I have broken a small patio (about sixty square feet) by hand and removed it and that was a three day job for me, and that's when I was young and intrepid. There is no way that I would take on something like that now.
posted by jcwagner at 1:05 PM on March 30, 2007

The best part about paying someone else to do the job, they take away the very considerable volume of waste.
posted by caddis at 9:24 PM on March 30, 2007