Cutting Concrete

[FlagCraig]

I need to cut 2' x 2' section of sidewalk concrete that is about 2" deep. Need to get to a pipe underground.

I use a DeWalt grinder for cutting metal at work. It's the base unit grinder that takes 4" blades.

Has anyone used a grinder to cut concrete and if so what blade recommendation. I've seen some at Home Depot/Lowes but looking for anyone with experience.

Thanks.

 

[68gtxman]

I use the masonry diamond blades in a grinder. But if you are going under a sidewalk, why not tunnel under it instead? You can use a rigid steel pipe and bang it in, empty, rinse and repeat until you get it all the way.

 

[5.7 hemi]

Normally a cement cutter (walk behind) would be used for this job. I wouldn't use the Dewalt, instead get a masonry blade for your circular saw and use that. You might need a couple of the blades, but the end result will be a faster and cleaner cut.

 

[conv67bdere]

X2

I've got the diamond masonry blade and it will work to cut the concrete . . .

Also agree, tunnel under it would be much easier . . . and you don't mess up your sidewalk either

 

[wsutard]

I would highly recommend also tunneling under it. However, if you do need to cut it then use the correct tool for the job. A concrete saw. It will make your life a lot easier and cleaner.

 

[747mopar]

I find paying a $30 rental fee makes it not worth the headache of using the wrong tool for the job.

Tunneling sounds like a lot if work but eliminates the concrete cutting and patching altogether. Good luck.

 

[FlagCraig]

I'm digging the tunnel idea (haha). Will go home tonight and eyeball it again.

Definitely a good digger. Post hole digger and auger.

That concrete saw looks like the real deal.

 

[68gtxman]

I find paying a $30 rental fee makes it not worth the headache of using the wrong tool for the job.

Tunneling sounds like a lot if work but eliminates the concrete cutting and patching altogether. Good luck.

Tunneling is not hard. I dug under my concrete sub base of my brick sidewalk with a hand trowel to put in a 4" corrugated flex pipe for roof drains. I dug from either side as far as I could reach and then used a scrap of 2" PVC and a mallet to connect the two sides. Easy peasy!

 

[Moparsmitty]

There are a couple of ways you can do this without cutting the concrete. If it's just 2' across, I would just dig under the sidewalk. I've done it a few times for utilities and unless the ground is hardpan or very rocky it's not that hard. You could also use a hard pipe and water pressure to drill under like this video shows.

 

[Superb Bee]

call a local sprinkler company and get the side walk shot, I would say they will charge you $100 to come out and shoot it, you dig the to and from, just hand dig down 12"s or so a little square.

Ig you don't want to pay anyone, you can do it with a garden hose or a pressure washer, simply dig down a bit and start blasting, years ago I used to do it this way lol, 2000psi cheap psi washer, take me about 20 minutes to get across a 36" walkway, I would go half way through one side and half way through the other, people tend to over think things, I would never cut a 2ft walk way to run a pipe under it, you have to then fix that walk way, made a bunch of work for yourself..

That being said if you have to cut the walkway and its 2" thick, and don't want to spend money on grinder wheels, simple grab a hammer and chisel, draw your lines, chisel a nice straight line about 3/4" down, and then pop the center with the hammer, it works better if you undermine it a bit but again, maybe 45 minutes of work... You can cut that time down by drilling 5/16" holes through the cement on your line every 4" with a hammer drill and masonary bit, then popping it with a hammer...


good luck

 

[YY1]

Pressure washer?

 

[747mopar]

Tunneling is not hard. I dug under my concrete sub base of my brick sidewalk with a hand trowel to put in a 4" corrugated flex pipe for roof drains. I dug from either side as far as I could reach and then used a scrap of 2" PVC and a mallet to connect the two sides. Easy peasy!

For some I'm sure lol. When answering questions like this one speaks from personal experience, unfortunately for me that means working on property loaded with sandstone where no shovel job is easy. I've literally got a rock as big as my house in the backyard with half a dozen more the size of a garage so I think differently.

 

[mmissile]

WEAR A DUST MASK!

 

[Fran Blacker]

If you use a gas powered cutter a mask like mmissle said and a garden hose to spray the cut will keep dust to a minimum.

 

[Superb Bee]

Pressure washer?

yah, best way to dig is with water a friend of mines son has a hydro excavator, google search that FUN....

I did a 2 second google search here is some boys doing it, it is simple, I was doing this 30 years ago, you can use a garden hose too, takes a bit longer , but just make a wand out of a piece of copper or pvc, put a straight brass old school nozzle on it and blast away...

If you use a psi washer, I would say it will take 10-15 minutes, no longer than that..

 

[Superb Bee]

I googled hydro excavator too for you guys, this is the same rig my buddys son has but his is on a Volvo cab and chassis I think with the truck it was 400k$ lol.. Hes also a mopar guy has some cool stuff...

 

[Superb Bee]

For some I'm sure lol. When answering questions like this one speaks from personal experience, unfortunately for me that means working on property loaded with sandstone where no shovel job is easy. I've literally got a rock as big as my house in the backyard with half a dozen more the size of a garage so I think differently.

I feel for you, I am having our "last" house built right now, actually living in or out of rather my buddies sons guest house (who I referenced above), he is contracting the house and 2 months over time, so we moved in lol!!! Find a contractor that will let you move in when they run over time And one of the issues was a piece of ledge the size of the house we are building infringing 35% of our sub grade excavation plot he luckily has huge hammers on huge excavators, but still took a lot of time to chip that ledge down...

That being said, NORMALLY, if there is a walkway it should have small materials under it, crushed stone, gravel, loom even... I did this for a lot of years, sprinkler installation sold out before the machines were affordable, so we did things the old school way..

 

[Kern Dog]

I work with power tools in construction and even with my experience, that huge saw
makes me a bit sketchy!

I recently did some roof work on my own house and had to cut some concrete tiles. I bought a 7 1/4" diamond blade to fit my Skilsaw. It cut the tiles fine but took time. It only cuts 2 3/8" deep too while concrete is usually 4" thick or more.
Tunnel through? This comes with its own set of troubles. What happens later when the excavated area allows the unsupported concrete to crack and shift?

 

[Superb Bee]

I work with power tools in construction and even with my experience, that huge saw
makes me a bit sketchy!

I recently did some roof work on my own house and had to cut some concrete tiles. I bought a 7 1/4" diamond blade to fit my Skilsaw. It cut the tiles fine but took time. It only cuts 2 3/8" deep too while concrete is usually 4" thick or more.
Tunnel through? This comes with its own set of troubles. What happens later when the excavated area allows the unsupported concrete to crack and shift?

Tunnelling needs to be done correctly not to "undermine" if you use a power washer the new pipe will be tight or to loosen the old pipe, then you can easily fil it back in, taking out 12" from a walkway that holds people is not a big deal at all, for example get a 2" thick slab made for holding say an a/c compressor, 36"x36"x1.75" and put it on a cinder block at each end, then tell me how much non impacted weight it takes to break it, Ill bet its a lot more than a person can weigh. But that is not the point, it will be plenty supported, we have done it hundreds of times and never had an issue.
I did 5ft walkways that were already cracked and never had a problem, I did block patios and never seen a paver move from its position.

As far as using a demo saw, that comes with a lot of bs, first gotta rent one which can be done at any home depot or lowes, then it takes 2 people to cut it one with the hose and 1 with the saw, then you gotta return it, and pay for it, it sucks... They aren't hard to use, I have one, its a stihl and I cut truck chassis in half with it and I am an old feeble ******...

 

[conv67bdere]

For some I'm sure lol. When answering questions like this one speaks from personal experience, unfortunately for me that means working on property loaded with sandstone where no shovel job is easy. I've literally got a rock as big as my house in the backyard with half a dozen more the size of a garage so I think differently.

Aww . . . c'mon 747Mopar, isn't that when you break out the tannerite ? ? ? ? ? LMAO . . .