Need to raise part of settled sidewalk?

Question

A section of my sidewalk has settled a few inches causing a tripping hazard. I plan on trying to pry it up with a long pry bar and putting gravel underneath. My question is: the section is about 9 feet long, should I cut the concrete at about 3ft. to make it easier to raise, or should I just try it as it is?

Answer 1

I have done this sucessfully. It takes a LOT of time and effort, so be warned.

Has it really settled inches or just an inch? If it is inches, you may have a much more severe problem. It is very unusual to settle more than about an inch, two at the very most.

It is going to be way too heavy for just a pry bar, even a very long pry bar. Cutting the concrete is no easy task either, plus it introduces additional problems.

What I do is to "tunnel" under the sidewalk section at each end. That is no easy task, but it is necessary. I then thread a heavy chain through the tunnel. Link the ends of the chain together and you have a loop to pull up against.

For that pulling, I run a wooden 4x4 across the sidewalk and through the loop of chain. Put concrete blocks under the ends of the 4x4 to hold it up. Put some 3/4 inch plywood on the sections of sidewalk beyond the one you are raising. Put an automotive floor jack on the plywood and another 4x4 going up to the loop of chain.

You then raise the floor jack and the chain and sidewalk section will follow it up. Once the section is up, you put the dirt or gravel under it. It is important that layer of gravel or dirt is as straight as possible. Any lumps will put strain on the section.

My description might make it sound difficult, but it isn't that bad. It does take a lot of trial and error to place the pieces in the right position. Don't ignore the plywood or the jack might break the other sections of sidewalk due to the pressure.

Again, this is really time consuming. It takes me at least three hours to do one section. That is typically 2 hours and 50 minutes of getting to where it will lift properly and 10 minutes once it is lifted.

Keep in mind that the section being lifted is EXTREMELY unstable and might fall at any second. Do NOT get your hands under it at any time, even for a moment !!!!

I figured this out after watching some pro's working on another section. They took a LOT more work than I did because they tried to put the jack under the section. The jack just kept digging deeper into the ground under the section. They kept putting more pieces of wood on top of each other, under the sinking jack.

It was a bit comical to watch. There were two rather large, strong men who kept doing the same wrong thing for hours :-) I'm not strong and I did it all alone and in less time.

Answer 2

Cut in into 3 sections and it will still be tough. You don't want to use a pry bar because you may crack the concrete.

Use wood 2x4s and wood blocks and take you time.

For under the concrete, don't use dirt. Use the special mix called base for block walls.

-tcw

Answer 3

i would put sand under it...if you dont get an even bed under it it may crack...once you raise it it may crack anyway , but its worth a try...

Answer 4

rent a forklift