Can interior concrete slabs be leveled without removing flooring?

In most cases yes. Polyurethane foam injection requires only 5/8-inch drill holes through the slab. If a finished floor such as tile, hardwood, or vinyl plank is installed over the concrete, small holes can often be cored through the flooring, the slab leveled, and the holes patched and refinished. Feasibility depends on the flooring type and degree of settlement.