[josephnyc]

Sure would appreciate some advice.

There's a 1/2 basketball court (20x25) made out of 2x4 slabs of concrete poured about 80 years ago.

Over those 80 years, the slabs have heaved and moved, with very very little cracking. The difference in height between them is at most 2", but most are less than 1"

I'd like to be able to do this job inexpensively, but well so that it lasts for years.

Could I put a 4" slab down right on top of this, with a mesh inside?

Vabor barrier? Foam between slabs? Sand between slabs? Rebar into old and new slabs to connect them?

Thanks very much,

Joe

 

[tgeb]

I'm an advocate for tearing things out and doing them over correctly.

But if you don't want to do a tear out, the next best thing in my opinion would be to break up the old slabs, cover with 4" of clean #57 stone, form and pour a nice 4-5" slab. I'd saw cut a few joints in it after the pour. WWM would be a good idea as well.

The stone "should" keep the old concrete from "reflecting" through the new.

The big issue would be are you prepared to raised the grade +/- 8" after the slab is done? Some places this just won't work.

 

[josephnyc]

I'm an advocate for tearing things out and doing them over correctly.

But if you don't want to do a tear out, the next best thing in my opinion would be to break up the old slabs, cover with 4" of clean #57 stone, form and pour a nice 4-5" slab. I'd saw cut a few joints in it after the pour. WWM would be a good idea as well.

The stone "should" keep the old concrete from "reflecting" through the new.

The big issue would be are you prepared to raised the grade +/- 8" after the slab is done? Some places this just won't work.

Thanks very much for the recommendation!

We definitely don't have 8" to raise the grade. Even 4" will be tricky.

I suppose what this boils down to is how stable the current 2x4 slabs are, right? It might be wishful thinking, but movement of 1-2" over 80 years means it's pretty stable, right? I'm not a concrete guy, so please tell me if I'm wrong -- no hurt feelings here.

Thank you!

Here's a couple of pictures:

 

[slowsol]

Are you planning to bring in dirt and level out around it when your new slab sticks 4" above grade?

Why take the chance. Just tear that old stuff out so you can get a proper subbase. 1"- to 2" inches? That seems pretty bad to me. Who knows how bad it is in the winter. If you don't tear it out, you're just going to be wasting money IMO.

 

[josephnyc]

Yea, I know you're right about taking it out.

I wonder if there's an epoxy or self-leveling synthetic rubber or some sort that I can just pour over it instead of concrete?

 

[brhokel606]

Are you a contractor? This is a straight forward answer to youre post, you can not do anything to stabilize those pads, there is nothing you can put over it to keep it from moving. The only option to demo it all, put down proper base and re-pour the pad. Rebar not mesh should be used. Hire a qualified concrete contractor and you will be happy.

There is no way to fix what you have, anything you try is throwing money out the window because the under lying pads will always move and ruin whats on top.

 

[brhokel606]

Sorry, double post...

What you do not realize is the concrete is constantly moving in each season because they are each independant of each other. This is an easy job really, not cheap but a good concrete job never is. Take some bids and never choose the cheapest, IMO there is a reason they are the cheapest.

If you do not know concrete work, this is not a DIY project. The finish is important and if you don't get it right it is also like throwing money away, especially when dribbling a basketball.

 

[tgeb]

Seeing the pics...

Tear it out.

Nothing is suitable for overlaying that.

 

[NYCB]

Come on, tear it out and put a new one in after checking the base. Anything else is just shoddy craftsmanship.

 

[josephnyc]

Okay, that's what I'll do -- get a few bids and let an expert take care of it (by ripping it out and starting fresh).

Thanks everyone!