My house once had a breezeway between it and the garage. Previous owners turned this breezeway into a finished laundry/mud room with a concrete slab underneath that cannot be accessed from the basement. On both sides of the breezeway are patio blocks.
The issue I'm having is during the winter this slab is heaving which is causing 3 of the entry doors to stop latching, as well as dragging along the door frame.
My question is, what can I do to eliminate this or lessen it? I want to take care of this in the Spring. My ideas thus far are to remove the patio block, dig down about a foot and maybe 3-4 feet along the slab. Along the slab I would fill with sand and gravel and then the rest of the area would be about 6 inches of sand and gravel.....I would use one of those powered stampers that you can rent and then lay down travertine pavers.
Would this be good enough? The reading I've done on this issue state that the ground should be prepared underneath the slab but I don't see that as an option any longer.......or is there some trick that professionals can do?