Cutting Concrete

Is there a way to score concrete that will allow me to break it with a sledgehammer?

A concrete pad was poured years before I moved into my house and it is right on the property line. I want to put up a fence and the post would be on my neighbors side if I don't make room by removing enough of the pad to allow the fence to sit on my side of the line.

Or, is there a way to cut out the concrete where the posts need to go instead of trying to cut the length of the pad?

Hope this makes sense to all. Any advice would be appreciated.

Reply to
Virtual.Voyager
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A diamond saw blade which is very expensive for the good ones. Call a mason who does repair work.

Reply to
Art

Lag down a brace and mount the post to that. Don't drive to put a post through the concrete.

Reply to
Noozer

The answer is yes, no, definitely, and maybe. Scoring will definitely help fracturing, but if there is wire or rebar in there, then that will have to be cut, either with an OA torch, or hand grinder. And if there is metal in there, it can eat a couple of expensive blades in a millisecond.

If you do have the luck of having no metal in there, just score the lines where you want it to fracture, try to go deep, even if you go through the concrete, and hit the concrete far away from the lines. If it DOES break off, you don't want any hammer dimples in the lines .

HTH

Steve

Reply to
SteveB

Yes & Yes.

How many posts? How thick is the slab? Any rebar or wire?

How good do you want this to look?

Saw cuts can easily be made by a commercial concrete cutter (even through rebar) but the cuts will extend into the "good" part of the slab.

Consider a triangular cut instead of a square cut....fewer saw kerfs into the good concrete

Maybe you could have the slab cored large enough to set the posts through it?

There are lots of ways to do this..... all depends on how much time & money you're willing to spend and what your desired end product is.

If the slab is thick enough you could just core a 2.5" hole & grout in pipe with an angle welded to it. Chamfer one corner of the post & lag into the post through the angle legs (both directions). Now you've got a permanent, moment resisting post base. Much longer lasting than a post in concrete but not the pretty thing.

cheers Bob

Reply to
BobK207

And watch as the lags rust out, and you have to do it again soon.

Do it once, do it right.

Steve

Reply to
SteveB

That's exactly why god made electric jack hammers, available at all rental places.

Reply to
valvejob

I don't see how a jack hammer is going to give him a clean, decent looking opening for a fence post at the edge of a slab.

Personally, I'd go with the advice to drill holes and use bolts. Once you cut notches into the edge of a concrete pad, leaving square inside corners, I think you leave it open to developing cracks and deteriorating. Plus, drilling holes sounds a lot easier.

Reply to
trader4

Using lag bolts and surface mounting the post to the concrete is no comparison to actually burying the post in the ground as far as strength goes. If you are using square posts, say for like a pvc fence, then rent a demolition hammer/chisel tool and notch out a square outline on the concrete surface, then chisel out the middle. You should only have to go down 4 inches. If you are using round posts, you can do the same with the chisel hammer or rent a core drill. I've seen posts that were lagged to the concrete that were ripped out when someone put excessive force against it.

Reply to
Mikepier

You can rent a concrete hole saw for a day. They come in various diameters.

One use is to cut a hole up to ten inches in diameter for installing an in-foundation safe.

If you go this route, I'd put in a 2" metal post, then, if necessary, bolt the 4x4" wooden post to it.

Reply to
HeyBub

so use stainless steel concrete wedge anchors.

Reply to
longshot

Stainless comes to mind... :-)

Reply to
<kjpro

Have core bits, will travel. :-)

Reply to
<kjpro

Funny then that lally columns are routinely used in a similar fashion to hold up houses. Or the two main posts that are holding up my front porch. They are sitting on the metal standoffs, used to prevent rot, and placed on top of the concrete porch.

If you are using square posts, say for like a pvc

Reply to
trader4

"Mikepier" wrote

Wow, a reasonable man in a sea of weeds. Lags are good. Stainless lags are good. BUT, when you lag close to any edge, there&#39;s a chance of splitting. Yes, they do work, as another poster mentioned when lagging columns to concrete WHERE THEY WILL BE TOP LOADED AND HELD IN PLACE BY THAT LOAD. No such circumstances with a fence that gets side loaded by wind, vines, weather, and climbing monkeys. AND, what about the lags into the posts? Are there going to have to be any corner brackets? How does one lag fence posts into concrete without something to join the two?

Yes, posts can be lagged into concrete. And, depending on where they are located in relation to the edge, can be done so reasonably strong. But you still have to have fasteners that will weather out, particularly the ones in the wood.

The OP asked for different opinions on how to do this. There&#39;s a hundred ways to cook a poodle, and it all tastes like chicken. There&#39;s a lot of ways to put up a fence, and you&#39;ll know if you chose the right way in about five years.

I, personally, tend to overbuild. I don&#39;t like doing the same job in five years.

Steve

Reply to
SteveB

-snip-

Remove the weight that is holding the tops of those posts and see what happens when you apply lateral force.

Jim

Reply to
Jim Elbrecht

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