[Red Squirrel]

Wow, what a workout. I only used it for maybe half an hour or so. Neighboors were having a birthday party outside and did not really want to disturb them, I really planed to do this tomorrow anyhow and they said it will be fine then.

This is the damage I have so far:






Just wondering if anyone with more experience can tell me a better technique to speed up this process. I'm drilling at an angle and trying to get the bit to slide through, which causes an inch or so to chip away all around, but getting entire chunks to break seems harder. The holes are the result of me not moving it around.

I've always wanted to try a jackhammer, so now I can say I've done it. Going to have fun tomorrow. Want to try to put in 6 hours or so to make the rental time worthwhile.

 

[josall]

Try a sledge hammer now you might get some bigger chunks.

 

[rustyjames]

Start from a corner and work inward. Keep the hammer on a slight angle.

 

[DexterII]

Technique can vary, depending on initial strength and age of the concrete, thickness, density of fill that it is under it, etc., but yes, with a slab like that, I would start in a corner, probably with a line of partial breaks with the jackhammer, a foot or so in, then smack the corner with a sledge hammer, and keep working across it like that. I assume anyway that you want to break it into managable sizes to be hauled away, not pulverize it. Some water on the surface will help keep the dust down, and with the steel toe work boots that you are wearing, it shouldn't make it too slick to work safely. And wear your eye and hearing protection.

 

[drtbk4ever]

This could make for a good A535 commercial...

 

[Red Squirrel]

I was thinking this overnight, no way I can finish that without renting it for like a week which would get expensive ($75/day), I think I will just bring it back and when I'll be off I'll rent a concrete saw instead, those should be able to cut through rebar right? I could just cut out blocks from it.

And yeah my right hand hurts today just from the little that I used it! Those guys that do this all day must have lot of pain issues lol.

 

[Bud Cline]

I'll rent a concrete saw instead, those should be able to cut through rebar right? I could just cut out blocks from it.

Nawh! I think you are kidding yourself with that theory.

You are on the right track with the hammer you have. You can determine the size of the chunks by where you place the point but you still have to chip it away from the rebar without having a cutting torch on the job. I wouldn't use that point you have if it was me, I would use a chisel-point. I think they (chisels) tend to break-away more than the pointy-point, the pointy-point tends to dig holes.

If you will allow the tool to do the work and not try to resist the vibration you'll do a lot better. It is normal to start a jack hammer and then try to hold the thing down and that isn't what to do. Drag it to a point, raise it almost straight upright, and pull the trigger. Hold on just tight enough to keep the tool in place. DON'T FIGHT IT. You won't win. As portions break away you can pry them apart a little then reposition the point and go again.

Getting started with a jackhammer is always the hardest part. Once you are going and have removed some spoils it really gets easier to gain ground. Loading it all out will be a different story however. There isn't that much there. Easy for me to say!

 

[Bud Cline]

Do I see a steel strip or angle along the edge? If so...is the rebar attached (welded) to it?

That steel edge is going to be an issue in getting started until you have removed enough broken material so that additional broken material has a place to move/fall to.

 

[DexterII]

Yeah, Red, I agree with Bud; stick with the hammer, make sure that you have all of the big pieces broken up, then ask a buddy with a set of torches to help you finish it up. And before you start loading, make sure that whever you plan to take it knows that there is steel in it, because some places do not want concrete with steel in it, so you don't want to have a truck or trailer load of stuff that you can't get rid of.

 

[Red Squirrel]

Good points, I think I will stick with the hammer then, I was scared to be on the slab while using it as I don't know at one point it will let go, but with all that rebar I probably don't have to worry. I can just try to cut out sections and as I cut rebar it should hopefully come apart more. I'll buy some steel toe boots to be on the safe side. I'll be off in a few weeks so I'll rent it again and have all week to go at it.

I'm not sure what's holding that angle iron but my guess is the rebar is welded to it. Guess I could test with a continuity meter. I do know that angle iron does not go into the house as I can put my nail between the end, and the house. Unless it's cut at some odd angle and part of it is going in.

Can I use an angle grinder with a cut off disc to get the rebar cut? I already have the grinder, just need to get the proper blades.

 

[Bud Cline]

Can I use an angle grinder with a cut off disc to get the rebar cut?

Yes you can, but rebar will gobble-up abrasive blades really quick. What size is the rebar? It may be that a set of large bolt-cutters may work.

How big is that slab overall anyway?

 

[kwikfishron]

As mentioned get that border out of the way first. Cut those bushes back and start on that outside corner. Your new grinder will cut the bar NP.

Am I seeing things or is that rebar just barley under the surface and the conc only looks to be 1 ½” thick?

 

[Red Squirrel]

The concrete is as thick as the metal L but it seems as I'm jackhammering it flakes off under, so those holes make it seem like it's not as thick. The rebar also seems to stop, so I'm wondering if it's not entirely full of rebar and maybe just the edges have some, though I did not do enough to know for sure.

If you click the pics they link to higher res versions so you can see the rebar better. It's the big stuff, so don't think snips would do it.

What about a propane torch, does that generate enough heat to melt metal? My guess is no, but it would be an easy way without renting/buying more equipment. If not I may just go the grinder route and buy a couple blades.

The guys that built this must have been used to building high rise buildings or something, this is serious work just for a deck lol.

 

[STL B.]

I'll rent a concrete saw instead, those should be able to cut through rebar right? I could just cut out blocks from it. Nawh! I think you are kidding yourself with that theory.

A powerful wet saw will eat that steel for dinner.

I'd have saw'ed it into 2x2 or 2x4 slabs and used the breaking hammer to loosen and pry them up and out.

If you hammer it all out without any cuts you will end up breaking the whole thing down to golf ball and smaller size pieces......a few tons worth.

Go with the saw........most rental shops around here will charge you for blade wear ( meaning they use calipers to measure the carbide and charge you for the % you used) and with what you need to do I doubt you'd use %10-%15 so it's not so pricey.

Your prolly done by now but if not consider renting the saw. Other than that I would recommend using a 1" chisel point and really working the hell out of it.....ie: use if like a pry bar after you get the tip buried......both feet off the ground/wildman type ****

 

[Red Squirrel]

My week off is still a few weeks away so I did not start again yet. I may stick to the hammer but I will also use my grinder with steel cutoff blade for the rebar. I'm thinking this may make things easier. I can't wait to get started again, actually. it will be much better without being pressed for time.

 

[STL B.]

You can get it done with a grinder but think of the mess and the time. It would take all of an hour or two worth of cutting and $50 worth of blade and you would have several manageable size chunks that are easy to dispose of.

Are you going to haul it off yourself or pay someone?

 

[Red Squirrel]

Not sure what I'll do with it after, it will sit in a pile till I figure out that part. I will probably end up getting the guy who does the weeping tiles to just haul it out as part of the job.

 

[DexterII]

Red, remember "The Great Escape"? Just stuff a handful in each pants pocket every night, and go for a walk around the neighborhood. Nobody will notice the slow accumulation of dust along the sidewalk!

 

[Red Squirrel]

Haha yeah, could just slowly get rid of it some other way.

I was thinking of just renting a portable rock crusher and then I could use it as backfill, then I realized just how massive a portable rock crusher is, and it's not something a typical DIYer would be renting. LOL

 

[STL B.]

I thing the portable rock crusher in the photo will bring it down to backfill size just fine.