There are a number of different methods used to repair foundations including: 1) slabjacking or mudjacking (which involves the injection of material under a slab or structure), 2) underpinning or piering (which involves the insertion of new or additional footers to support the structure), 3) helical piers (which look like large screws that are inserted into the ground below your structure to support a new footer), 4) jacks or lifts (which raise the slab or foundation so that a new footer can be placed under the structure.