[Osiris]

Hi,

We have a concrete slab in our back yard, about 15' x 10'. I assume it used to be level, but I am guessing there was some settling underneath and now it is not level. I talked to one contractor who said the whole thing would need to come out and a new slab poured, but I am skeptical. Is there any reason you can not pour something like self-leveling concrete on top of this to level out the slab?

 

[Jamamros]

What you need to do honestly, is "cheat the trade". You need to call a few companies for "estimates", and each time they come ask that question, "Does the WHOLE thing gotta get replaced?" If you get plenty of yes's, then do it. If not, I would simply flash patch it with either hydraulic cement or see 10-60 or 10-61 Rapid mortar. The rapid mortar would be best b/c it allows you to do entire horizontal surfaces, and is used for strength gain.

http://www.buildingsystems.basf.com/productdetailPage.asp?prodID=1

 

[Yoyizit]

We have a concrete slab in our back yard, about 15' x 10'.
now it is not level.

You could roughen it first
http://www.csunitec.com/masonry-tools/scouring.html
and then put concrete on top, but I think the minimum thickness for a layer of concrete is 2".
You may want to embed wire screen in the new layer.

I have the same problem in my driveway but I need the edges of each slab to line up so I can't add thickness.

 

[Scuba_Dave]

How far out of level?
I think I'd either use as is if not too bad or build a level wood floor over it
Or build the walls to adjust to the dip
My old shed is not level
I made the mistake of making the new 10x10 addition level

 

[Maintenance 6]

Dave asked the right question. How far out of level is it? If it isn't terribly far out, then compensate in the wall construction. Many shed/garage floors are poured with slope for drainage.