Cutting concrete floor?

[Davej]

I've heard that hitting rebar with a diamond blade can quickly ruin it

-- so what do the experts do?

[Eric in North TX]

How about using an abrasive blade?

[Davej]

They are extremely slow cutting. I don't know if you could perhaps switch back and forth?

[evodawg]

I usually cut concrete about an inch deep, hopefully rebar is deeper. Then use a jack hammer to remove it. Cutting the concrete an inch deep just keeps it from cracking beyond those cut lines. Sort of like a expansion joint.

[Edwin Pawlowski]

They use diamond blades. If you have a lot to do, it may be close in price (and much easier) to hire a pro. You can get a good ballpark price on the phone.

[Oren]

This is way we cut mine in a bath remodel. Used diamond blade for the "relief cut (?)" , the a jack hammer.

Check to determine if the foundation has post-tension cables. You do NOT want to cut one of the cables.

[BobK207]

Good quality diamond blades and core bits will cut through rebar with little more effort than concrete alone. Water cooled is the way the pros do it.

The concrete cutting contractor that I've been using for nearly 20 years has cut through all sorts of messed up RC for me.

When Marty cut mounting holes for me in a chuck of concrete we hit a #9 bar that was misplaced. The 3" core bit bisected the bar such that I have (somewhere in my "that's cool" stuff) a chuck of #9 bar about 2 3/4" long with the inside diameter of the core bit curvature on both ends of the chunk.

The floor of my lab was 24" thick with 2 mats of #6's at 12" o/c both ways. To install a huge piece of machinery we needed to cut an access hole in the floor. It was cut by another contractor using a 60" diameter saw.......rebar didnt even slow it down.

Hilti water cooled core bits (vacuum base drill system) can core concrete with rebar as fast as you can advance the bit (within reason) .....12" hole in a minute or two.

What are you trying to do? demo? remodel? slab crack control?

cheers Bob

[DanG]

Cuts right on through. I'm sure it eats more diamonds, but there are few choices. I prefer wet cutting whenever possible.

We just did some cutting that had 3x3x1/4 angle iron suspending concrete over a tunnel space. One of my guys cut right on through the angle iron. I did tell them to raise the blade whenever they were getting that kind of quantity of sparks for the rest of the cuts.

[Davej]

All I want to do is install a sump system around the perimeter of a

50yo basement.

[BobK207]

I would use a water cooled saw but I have access to a MK Diamond Walk- Behind Concrete Saw.

If I didn't I would consider renting one or hiring a commercial concrete demo guy. If the basement is more or less "clear" he could zip around the edges of the slab in no time .... cutting all the way through, which would make your job eaiser. No mess, no dust, no noise.

If he didn't have a helper you could work with him shop vac'ing up the cooling water to control the mess. Set up a sump pump in a watertight trash can & you'll way to handle the water when the shop vac gets full.

The other posts about a partial cut to prevent random cracking & a jack hammer are good ideas but much slower and more work.

cheers Bob