Concrete sidewalk replacement

[Wilfred Xavier Pickles]

Midwest US. There used to be mines under this area: coal and later fire-brick. Find a nice flat spot today, come back in a day or a week and there's a sink-hole.

Private sidewalk on the side of a hill. One section (36 x 56 ") slowly settled all a-kilter, one corner 2" above grade, the opposite corner

2" below. I paid a contractor $50 to bust it up, haul away. He wanted another $250 to replace it: I knew what he'd do, decided to do it myself.

The proper level of the sidewalk is the same as grade. In the hole left by the removed concrete, it's about 2" to grade on the upside, about

6" on the downside.

The contractor would have framed, poured and leveled gravel, then poured and finished. Over time, the same problem would have developed. This is approach #1.

Approach #2 would be to dig and level the dirt in the hole, then maybe gravel and pour/finish. Over time, same problem.

Approach #3, which I'm considering, would be to use a fence-post digger to dig several piers/footings, just like for a fence-post, and concrete with a re-rod up to about 2.5" under grade. Then some gravel and 3-3.5" of concrete, cold-bonded with the piers.

This "project" is a severe PITA for poor me. My back (and some other parts) is killing me, and I've broken out in some kind of hot-weather rash that torments the mortal s*** out of me, day-in, day-out.

If anybody's got constructive suggestions, other ideas, or ???, it would be much appreciated.

Thx, Will

[chaniarts]

what makes you think 1 or more piers won't move either?

[Don Phillipson]

Instead of a single smooth concrete walk (all 3 variants proposed) why not use pavers on a gravel/sand bed? If they rise or fall (slowly) even as much as 2", this would be progressive and you might not even notice.

[Jim Elbrecht]

That was my first thought, too.

And when they do 'sink' it is a simple task to re-do what needs fixing and not touch the rest of the sidewalk.

Jim

[hallerb]

yeah in this application pavers are the way to go

[Jay-T]

It's too late now, but if the original slab wasn't damaged, another option would have been to reposition it back to level and pack dirt under it so that it would be level. It would have required crow bars or 2x4's (or

4x4's) to pry up the low end, and dig or wash out the dirt from the high end. Then repack underneath until it is level.

[Wilfred Xavier Pickles]

Front lawn slopes down to the public sidewalk. There's 4 steps up to front porch level, then the problem sidewalk square.

Pavers?

1.) It would look muy mucho funny (wouldn't match existing concrete sidewalk). 2.) The surface prep doesn't sound any easier than what I'm contemplating with concrete.

Thx, Will

[Wilfred Xavier Pickles]

Well, that occured to me long time ago. I ran it by the contractor, he muttered something about mud-jacking that he wasn't equipped to do.

Thing is, I'm the only one on the job. Neighbors went into hiding soon as the work started.

Thx, Will

[krw]

For larger jobs, the section can be re-leveled by pumping concrete under the slab. If there is a sink hole, and not just a rotted root, or such, nothing is going to be permanent until the underlying problem is fixed.

[aemeijers]

Don't blame 'em. That concrete stuff is HEAVY. :^)

[Jay-T]

I know what you mean. Contractors never seem to like my ideas. And, it can be a bit of a strength trick sometimes trying to get the slab lifted even with good leverage. I have also heard people talk about mud jacking, but I think that only really works with larger slabs such as patios, and it does involve special equipment, drilling, etc.

For one fairly large sidewalk slab that I wanted to level, I came up with an idea that worked well. I happened to have a small 20-ton hydraulic jack for something else I was doing, so I decided to try using that and it worked. I dug out an area under the slab, placed the jack under it, used a wood block on top of the jack, and jacked the slab up. Then I packed it underneath with dirt to keep it level and removed the jack and filled in the hole. Worked like a charm and it was fun. Just some digging on my part and no heavy lifting.

[Colbyt]

As much as it hurts me to say it and you to hear it your initial option2 is your best course of action.

Be sure not to disturb the soil below the removed portion on the high side. I would use a sharp spade on my hands and knees to pare it off then compact it with an 8x8 hand tamper. Water and compact whatever gravel fill you add.

I would also use 1/2" isolation joints between the old and the new concrete. Then perhaps if you need to you can jack it up in a few years.

Good luck.

[hallerb]

: [e-mail]...

=EF=BF=BDAnd, it can

a buiddy of miner lifted and straightened a single monolith of 8 large concrete steps with a jack. worked great

[Wilfred Xavier Pickles]

On this hill, the underlying problem is "Gravity" (not fixed anytime soon). :-)

I figger I take the fence-post digger straight down 36+", it oughta hold up a long time. The stuff on the surface slides down the hill the easiest.

Will

[krw]

If it's the hill eroding away, fix that first.

When it fails, and it will, you'll *really* curse yourself out.

[aemeijers]

Not eroding, slumping. All hills other than exposed ledge do it. Dirt isn't really a solid. and it like to find its own level, especially when saturated with heavy rain. Gravity is a bitch that way.

Hillside houses, as common around around lakes, are notorious for slump problems. Unless special precautions are taken with foundation, the whole damn thing wants to slide downhill. Decks and sidewalks crack and sag quickly. Slump is why retaining walls by the driveway cuts on split-levels often fail. Ditto for cheap roads cut across the side of hills.

[tango]

If there are mines underneath, you have to put posts all the way to the floor of the mine. Get a pile driver and drive several hundred feet of steel well pipe until you are below the floor of the mine by at least 6 feet. Put several of these under each slab, then fill them with concrete, and finally pour your walk.

Someday you'll wake up and your house will be in the mine, but your sidewalk will be where it belongs. Cool, hey !!!!

Of course you could just use patio blocks for the walk and when they settle, just lift em and add more sand.

[John Gilmer]

Why even bother with "moving" pavers.

Just tear up concrete that has shifted too much to be usable and get course gravel more or less like you would use for your driveway.

IF, in the fullness of time, things stop moving about you can put in "permanent" sidewalks.

Frankly, if you don't NEED pavement on a driveway or a "sidewalk" don't install it.

The most of the rain on gravel will simply sink in right where it lands. If you have pavement, the water goes someplace else where it can cause erosion or other problems.