I need to remove a 4″ thick concrete door threshold. Its probably 5 years old and sits on a concrete slab I don’t want to damage.
I started with a sledge hammer with little to no effect, the hammer drill was useless, so I rented a 25lb demo hammer with a sharp point bit. It sort of worked but the pace is very slow. To rid of the 4″ thick 3′ wide and 8″ deep threshold would take hours with the demo hammer.
The only I can think of is rebar? or the fact that I pushed down a lot on the hammer, which according to my seach for this topic a few minutes ago is wrong. Any thoughts? I’m a homeowner and my back is killing me. And desks jobs make you a wuss, but I really like doing things my self.
Replies
Rent a concrete cutting saw and score the concrete so it breaks easier. Or drill a bunch of holes with a good rotary hammer.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Let the hammer do the work as I'm sure you found out. By leaning on it hard, you took most of the abuse meant for the concrete. Scoring gives it a place to go, might help. Grind the rest off when you get most of the big stuff gone. BIG DUST.
A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
a secret i learned with buting cement is stay in one spot and get it cleaned out.the start slicing pcs. off. first time i used a jack hammer i'd hit a little here a little there,took forever. larry
hand me the chainsaw, i need to trim the casing just a hair.
Give us a little more background. What's the purpose of demoing this? What kind of surface do you want to have when you're finished? Will this remain a door opening, are you going to put a wall there? What was the reason for the high threshhold, maybe some drainage issues?
-- J.S.
I'm removing this theshold to make the door a window. It does not need to look pretty because it will be covered up. Thanks all for the suggestions.
In that case, could you just run deep kerfs with a wet diamond saw where the edges of the new plate will go, and just break away the stuff outboard of the kerfs? Cut 'em deep, smack 'em with a sledge, it shouldn't be that hard.
-- J.S.
Excellent idea, I tried this with a bit of success with my circular saw and a masonary blade going only a 1/2" at a time. It was a major pain, but worked the best out of everything I tried.I know there is no way to get a big wet saw that rolls along on wheels in this small space, but I hope a 12" cutoff saw will work. It's cetainly more powerful than my cheapo circular saw. I will try this in two weeks and report back. Thanks again all.
Look for a place that rents the Partner K-3000. Here it is on their web site:
http://www.partnerusa.com/node47.asp?product_id=k3000_spray
Be forewarned that it's a messy beast. It flings water and micro-fine ground up concrete with amazing force and volume. So tarp things well.
The soft start electronics are excellent on it. You can even get away with using it on a 15 amp circuit if you're careful. If you have a full 20 amps to yourself, no way can you trip the breaker.
-- J.S.
Edited 8/9/2006 8:30 pm ET by JohnSprung
Somethings wrong.
It took me 2 hours to demo an 8" thick x 6' wide x 25' long sidewalk.
Your little threshold would only take 15 - 30 minutes.
If the 'hammer is vertical, apply no extra pressure, let gravity do all the work.
If it ain't vertical, try to only apply as much pressure as gravity would if it was vertical.
If you are trying for a reasonably clean, straight line break, move the point along the desired line fairly quickly, back and forth untill it cracks off along the line. Three or four impacts, then move. Repeat. You'll hear the difference when it cracks.
If you are just trying to "get'er done", hold the hammer in one place till it penetrates. Try for 6"-8" chunks.
If there is rebar, you'll need a couple of large hammers and a hacksaw. The sledges are for breaking small floaters that have stuck to the 'bar. Hold one sledge behind the piece for an anvil and hit with the other.
Heavy boot, clothes, and eye shields are absolutely needed.
Diamond blade on an angle grinder. Gets into tight spaces better than a saw.
Wet or dry, both blade types are available, $15-$20 or so. Dry would kick up a CLOUD of dust, though. If outside, just close up the house first, and wear a respirator. If wet, plug it into a GFCI receptacle, just in case.
Of course, safety glasses (goggles better) hearing protection, hat, gloves, long sleeve shirt, the works.
Be safe.
Pete Duffy, Handyman