Our Back patio was poured in the early 90's. Half of it was covered under a large roof overhang with the rest exposed to the elements with concrete steps coming up from one side of the slab. There was one long expansion joint dividing the inboard and outboard slabs running parallel to the roof, right under the roofs eavestrough which when it cracked and the water ran over the eavestrough edge, it ran right into the expansion crack eroding the base under the concrete...... The Patio was divided by this expansion joint and 3 others running the opposite direction, which created for all intents and purposes 8 floating pads, which when they cracked and began to sink at different rates, they created trip points everywhere, with some pads pulling away form each other. The cost to replace was crazy. Ross explained to us when he came out to perform the quote that because some of the pads had pulled away from each other when they dropped they would not fit back perfectly as when the slab was first poured but close, eliminating the trip points and giving us back our patio. Very Happy with the work Ross and his crew did for us and have already recommended him to another friend, whom Ross has already lifted his exposed aggregate driveway for him.