I just had a contractor poor a concrete slab, 24’ X 28”, for a garage. The problem is, he didn’t get it level (or square), it slopes away from the highest point 2 ˝ inches in all directions. I realize I can still frame this, but that requires me to build the walls out of square to compensate. Does anyone know of a good floor leveling patch that I can use? Or some other technique that might be helpful?