My patio is on a slab, and it had become uneven - lower on one end, and higher on another. I called CRC Concrete Raising and Repair, and they sent an estimator out to look at the work. He surmised that I had a root problem on one end. He was very upfront about the fact that they could possibly not get it to go down all the way. The crew showed up on time, and went right to work. They worked as hard as could be expected to get that one side back down. They pumped and pumped under the slab, but it is still about three quarters of an inch high. It is not "perfect", but it is a lot better than it was! I am glad that they explained the extenuating circumstance to me in advance because that way I did not have unrealistic expectations about what they could do. As far as the company itself, everyone I met was a real professional. They all seem to be very customer-oriented, and they are very easy to work with! .