Foundation Wall Bracing - Bowed Walls

Residential

Foundation walls which are inherently weak, inadequately connected to the floor system, or walls which are subjected to relatively high soil pressures, may fail and move inward.

Block Foundation walls will generally bow in at the center 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, as shown in the first picture below left, or by running tie back anchors into the soil. To straighten the foundation wall generally requires excavation of the exterior. If the block foundation wall is severely cracked and bowed bracing or tie backs will not be effective and we generally recommend foundation replacement.

Concrete foundations generally hold together much better than non steel reinforced concrete block foundation walls. Inward movement along the top of the concrete foundation wall is generally caused by a failure of the connection between the top of the foundation wall and the floor framing. This failure can be due to an inadequate number of anchor bolts connecting the sill plate to the foundation wall, no nails connecting the floor joists to the sill plate, the foundation wall running parallel to the floor framing with no provision for bracing the foundation wall along the top, or a framed knee wall built between the top of the foundation wall and the floor framing. Some early signs of concrete foundation wall movement include diagonal cracks at the corners of the foundation wall with a vertical crack located near the center, and the foundation wlal is leaning into the basement or crawl space.

At Structural Dynamics, we utilize several methods to stabilize a concrete foundation wall which is unstable and has moved inward along the top. Some examples of foundation wall stabilization are show in the pictures below.