I have a slab that is a the last 6' x 6' section of the sidewalk to my front door and it has settled on one end so that water that lands on it runs toward the house and goes down around the foundation as the door is in a corner. It is not causing water problems under the house but I guess it could down the road. So I initially thought I would bust out the slab, build it up with some granite sand and pour a new slab. However that comes to 20-21 bags of crete and I can't mix it and pour it fast enough, so that is out. I also can't get one-third of a yard delivered. I could just level it with granite sand as I am going to cover this area(more on that below), but the water would end up in the same place.

So I wondered if I could get a few bags of the leveling portland mix and pour it on top of the existing slab to give it the proper angle? It would be almost 2 inches thick on the low end and then taper down to the edge. There is a joint between this slab and the next slab, so I could run it into the joint?

I am not worried about the looks because I am going to build a landing above this section and the concrete will no longer be visible after that. I just want to keep the rainwater from running into the corner.

Would the Portland mix adhere to the old concrete or would water just migrate along the seam and go in between the 2 layers? Just trying to figure out the best way to keep the water out of the corner. Thanks for any opinions!

can you jack it up and fill under it,

We had similar issues with a patio slab drooping in a corner, hired a company, they come out, place jacks in the corner lifted the slab, then drill a hole in the slab and fill the void jacking up the existing concrete.

Look for a concret raising business. Also called mud jacking. Works well. Or a custom concrete curb guy, they may be willing to pour a small slab.

I would expect your fears of water migration is correct.

There are a lot of potential problems with putting a thin layer on an existing slab.

Since it is only 6 x 6, why not just break up and remove the old, then lay a new one properly ?

Even if you hired people to do it, it wouldn't cost much.

You can rent a mixer and do the complete job yourself.

You can do it, but I doubt the new layer will ever really be sealed or attached to the old layer. And the thin edge will eventually start cracking and spalling off in pieces. If it's all going to be hidden beneath a deck of some type - I'd probably do it anyway and to heck with how it seals or looks...

Other option is to dig some kind of drain to get water away from the corner.

Short answer is no. Depending on the material used you need anywhere from .25"-1.5" coverage. The thin side will crack and fail especially when exposed to water.
I would demo it and pour it. You'll have plenty of time to pour 20 bags of concrete before it sets.

They will expand and contract at different rates and the thinner layer will break up fairly quick.

Jack up existing pad. If that doesn't do the trick, redo. 6x6' is about 0.5 cubic yards at 4" thick. If you're cheap but handy, you can demo, frame and prep the surface and then find someone to come do the finishing. The buggy of concrete will be $50-100.

Or just write a check for a contractor. Still affordable.

I'd rent a small Bobcat with front bucket and jackhammer attachment. And get a Dumpster. Rip it all out before the landing goes in. Remove topsoil up to the front wall. Lay in clay soil, grade it away from the house and tamp it good. Then replace the topsoil.

My dad had a similar issue with a concrete patio build into the "L" of the house. Over time it settled towards the foundation as well a perhaps pushing in the interior basement wall; a healthy ½" crack formed and water would shoot out like an artesian well.

Basement drainage was added and the crack sealed but the issue remained. Before the latest deck was installed I removed the slab with a 180CFM compressor and 90# jack; we rented a U-Haul pickup truck and drove the concrete to a clean fill, one ton at a time.

Basement has been dry ever since.

My brother had this exact problem w/ a slab at the entrance to his house and the easiest and best solution was as others have already mentioned, jacking and pumping underneath.

Worked pretty good.

I believe this product will work for what you want. Just make sure the concrete beneath is clean and slightly damp when you mix and pour this on. It is extremely durable. Just make a form,mix it up and pour it in.

The last time I purchased it,the price was around $50.00.

https://www.paintdocs.com/docs...&prodno=035777003626

Sherwin Williams sells it

This message has been edited. Last edited by: wcb6092,

quote:

Originally posted by wcb6092:
I believe this product will work for what you want. Just make sure the concrete beneath is clean and slightly damp when you mix and pour this on. It is extremely durable. Just make a form,mix it up and pour it in.

The last time I purchased it,the price was around $50.00.

What product was that again

I vote for rip it out and re-pour.

Well, I can't jack it up without removing the surrounding perfectly level pavers. I doubt they would ever be level again, if I did.

I guess it is demo time. I will rent a jack-hammer from the Depot and get after it. The stairs will be a bear as they are poured in place concrete and I can see the rebar ends on one side so it will be interesting. The plywood forms are still on the bottom of the stairs. I am sure it will be fun. Wish me luck.

And if you get part way into it and start to feel out of your league, don't hesitate to call a concrete contractor in at some midpoint.
That happens A LOT and they are used to it and happy to help.

(Don't ask me how I know this. :| )

Ditto on Riley's comment. I've seen driveway's leveled for over twenty years, drill hole(s), inject a sand mixture under pressure to raise the concrete. Now they have a foam that does the job. The concrete will match since it's the same concrete that was poured originally, no excavation, no mess.

Or call one of those stamped concrete guys and have them add 1.5-2" of stamped concrete on top and they'll slope it.....and do the entire walkway in something decorative. They usually charge $1.50-2 a sq foot.......Here they pour a slab, then long after it's set, add the thin coat and stamp/color/seal it.

Another option is to tear it up and put pavers in that area.....they drain and are easy to level.....

This is one of those jobs that's probably cheaper to just pay a professional that does it everyday.

quote:

Originally posted by cruiser68:

quote:

Originally posted by wcb6092:
I believe this product will work for what you want. Just make sure the concrete beneath is clean and slightly damp when you mix and pour this on. It is extremely durable. Just make a form,mix it up and pour it in.

The last time I purchased it,the price was around $50.00.

What product was that again

I vote for rip it out and re-pour.

https://www.paintdocs.com/docs...&prodno=035777003626

H&C Broom Finish

if it were up here in the frozen north I'd say rip it all out.

but since the ground down there won't freeze , I wonder about just pouring the new over the old

When I bought my house the concrete slab floor of the garage had sunk about 2 inches. I opted to have it lifted and they drilled holes and pumped in material.
That was three years ago and the slab has remained in place so I'm pretty happy with the results. The best thing was that it was quick and didn't cause a huge mess.