Because shifting and sinking soils caused by mine subsidence can seriously damage concrete block foundation walls, the Illinois Mine Subsidence Insurance Fund has sponsored the development of a new repair method. This new method: gives an aesthetically pleasing finish; costs less than equivalent alternatives; needs no special equipment or hard-to-find materials; and can be performed easily by local contractors. THE RETROFIT TECHNIQUE The cracked foundation wall is strengthened by external steel reinforcing straps attached to both sides with epoxy, then covered by an aesthetically pleasing, crack-resistant fibre-cement. PREPARING THE STRAPS The correct strap size depends mainly on the foundation soil, the wall characteristics, and the additional ground movement anticipated. A qualified engineer should determine the strap size on a case-by-case basis. PREPARING THE WALL The wall must be prepared to ensure proper adhesion of the epoxy and fiber-cement. If the wall has been painted, the paint must be removed. MOUNTING THE STRAPS Proper strap placement depends on the stresses expected to act on the wall and should be determined on a case-by-case basis. Mine subsidence often causes stresses that place the top of the wall in tension. In such cases, place the strap horizontally as high on the wall as possible. Next, seal the strap with a generous amount of epoxy paste. After the sealant epoxy has cured properly, inject the steel strap with epoxy. The wall is now ready to be covered with fiber-cement. RESULTS This retrofit technique was tested in the civil engineering lab at the University of Illinois. The results from these tests showed that the retrofitted walls were stronger and stiffer than the undamaged walls.