Unlevel Concrete Slab for Shed

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

Osiris said:

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

Click to expand...

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.

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

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.