Concrete masonry basement walls can crack, bend, buckle, or tip from unanticipated lateral earth pressures. Even basements built according to code can be structurally deficient, since codes represent minimum standards, not necessarily what actual site conditions may require. Though ideally a structurally deficient basement wall would be torn down and rebuilt, this usually is far too expensive to be practical. The next best solution: Correct the problem before it becomes too serious. Here are five techniques. If properly engineered and constructed, they will strengthen and help prevent further deterioration of concrete block basement walls. TECHNIQUE 1: VERTICAL STEEL TUBE REINFORCEMENT When basement walls are bending vertically or horizontally but aren't yet badly deformed, vertical steel tubes placed inside the basement can prevent further deformation and stabilize the walls. This method is relatively inexpensive and requires no exterior access or excavation. TECHNIQUE 2: STUD WALL Alternately, a stud wall that resists lateral loads and part of the vertical load can be installed within the basement. TECHNIQUE 3: EXTERIOR AUGMENTATION Placing a reinforced, grout filled block wall outside an existing wall can be effective if the existing wall is badly deformed but still capable of supporting the structure. TECHNIQUE 4: CANTILEVER RETAINING WALL A second wall can be built inside, as well as outside, the basement. A reinforced, poured-concrete retaining wall inside the existing wall will resist lateral loads, while the existing wall supports the vertical loads. TECHNIQUE 5: BUTTRESS BLOCK AND GIRT Designed for heavier loads than the stud wall but lighter loads than the cantilever retaining wall, the buttress block and girt method is a simple and flexible solution for distressed walls.