We are remodeling a farmhouse and have a problem with a mudroom that was added to the house in the 1920s. The footing is only 24" deep and we're in Michigan. It has heaved and cracked across the entire width in one spot, causing the brick on the exterior to crack at the mortar about 1/2" in two spots. Three builders don't seem to think it's a big problem and a fourth proposes rebuilding the addition entirely. When pressed, one of the builders said we could watch and see what happens, then dig down and pour some concrete underneath if the heaving continues.
I'd like to know how we might reinforce the slab now in an effort to prevent any future heaving.
I realize that the ideal solution may be to tear off and rebuild the addition over a proper footing, but that is beyond our budget, especially for a mudroom/extra 1/2 bath.