I had an additional patio slab and a wall built against the original patio of my home about five years ago. The added structure began to sink and separate from the original, causing a crack in the wall and a slight difference in height between the original and add-on. I called CRC, they sent Mr. J. Raymond, who assessed the situation and explained in detail what and how they would remedy my situation. He also explained, the only thing he could guarantee was that their treatment would halt my patio dropping any further. He couldn't guarantee it would raise to the original level. I was willing to accept that.
The technician, Billy, arrived a few days later, again explained what they would do and how, and told me he would do his best to raise the patio. He was very affable, professional and proficient. He entertained all my questions, showed me how the machine and process worked, and walked me through the process before he began.
To my utter satisfaction, he raised my patio to the original height and closed the gaps and cracks in the wall. I would highly recommend CRC services. They exceeded my expectations, In addition, they sent me a dozen chocolate chip cookies, with a recipe to make my own, as a thank you gift. Fantastic!