Concrete block foundation walls which are inherently weak, inadequately connected to the floor system, or walls which are subjected to relatively high soil pressures, may fail in their ability to resist the lateral earth pressure and bow or move inward.
Block Foundation walls will generally bow in near mid height and develop a horizontal crack which runs the length of the foundation wall at mid height. There may also be diagonal cracks at the corners extending from the basement floor to the top of the foundation wall. If the bowing and cracking is not too severe, the foundation wall can be stabilized against further movement by bracing it with vertical steel beams placed against the wall. These beams are bolted into the floor framing above and the concrete floor slab below. If there is no way to bolt into the floor framing above, then the installation of a tie back to restrain the vertical beam brace may be required. To straighten the foundation wall requires excavation of the exterior and we generally don’t recommend that for a block foundation wall as the back filling process may damage the wall even more. If the block foundation wall is severely cracked and bowed, bracing will not be very effective and we generally recommend installing a new wall in front of the existing wall or replacing it.