We have a concrete slab at the edge of our patio which is jutting up at least 6 inches on one side. This and two other pieces were apparently added after the original patio was poured. Since we bought the house in 1991 the piece at the corner has jutted up a little more each year. Someone said a root from the sycamore tree about 7 feet away was causing this. How can we get underneath the slab, and what should we do? Should the root of the tree be cut off, and if so, will it grow back?