Foundation Leveling - A catchall phrase which generally describes the process of underpinning a slab foundation or shimming a pier and beam foundation. No reputable foundation company will claim to level a foundation for two reasons: 1) the foundation may have been built to a tolerance of +/-.75 inches or more, 2) the aging process of concrete and wood may preclude lifting the foundation to an approximation of its "as built" flatness. The wooden structural members are notorious for taking a permanent warp and may not adequately respond to foundation lifting. This is another reason why foundation repair should not be delayed.