My front porch (stoop) is a 5'X 4' concrete slab that has starting sinking at the front and pulling away from the house. To make matters worser, there are pillars that hold up an overhang involved. As the slab sinks, they are pulled forward, which pulls the overhang from the front of the house. Can this problem be repaired, or is the only option to demolish the entire mess and start over?