Cutting concrete sidewalk?

My niece wants to increase the size of a hole in the sidewalk where a tree is growing. It looks to me like the job would require cuts of about 8 feet of concrete -- five feet along one edge, and three along another edge. I haven't dug into the thing to see how thick the sidewalk is, and I don't know if there's steel inside. I do want to make clean cuts, so a big sledgehammer isn't the right approach.

What are my options for cutting the concrete? I've seen guys with a tool that has an abrasive blade -- or maybe it is diamond -- and a chainsaw engine. Is that the right thing for this job? I've also seen guys with big water-cooled saws which they walk behind. If that's the right tool, it isn't a DIY task. What advice does anybody have?

You can rent a saw for cutting concrete and other manufactured 'stone' materials. They do use an abrasive type blade and work well. Eye and ear protection as well as dust protection must be worn... ;)

This is what I use to cut concrete and rebar. It will make quick work of your job. You should be able rent one at a local rental center.



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If you can, get one with an attachment for a garden hose. The water keeps the blade cool and keeps the dust down.

The walk behind will be much easier for straight cuts. There will be no rebar in any normal sidewalk.

On a complete separate note, the hole should be the same size as the canopy of the tree. Any tree that is forced to grow in a smaller hole in concrete will eventually fail. This is why there are only a few trees that will survive this on a long term basis.

As Greg says, rent a walk behind one. They are water lubricated so no dust and easy on your back. Cheers

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Originally Posted by Greg R Bradley

The walk behind will be much easier for straight cuts. There will be no rebar in any normal sidewalk.

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There may be concrete mesh in the side walk. If this is a walkway along the road/street, you may run into code problems with your local government.

Most light duty walk behind rentals come with a diamond blade requiring a water supply, they don't even know reinforcing is there. But most walks are non-reinforced so it should be a non-issue.

Do the rental places make you buy a blade???

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Originally Posted by George Bokros

Do the rental places make you buy a blade???

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Normally no, unless something "unusual" happens & you break the blade, but that would be quite unusual. Diamond blades usually wear well & the eventual replacement of a blade should already be factored into the rental cost.

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Originally Posted by Al Launier

Normally no, unless something "unusual" happens & you break the blade, but that would be quite unusual. Diamond blades usually wear well & the eventual replacement of a blade should already be factored into the rental cost.

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Rental places that we have used measure the blade going out and when returning. They charge you for the wear on the diamond blade.
Lee's correct on mesh possibly there on newer sidewalks. These tools go through the mesh like it wasn't there but the mesh makes it harder to break up the pieces you are removing.