Ask The Expert: Can my bowing basement wall be saved?

Thursday, August 8th, 2013 by Tim Warchol

Bowing Block Wall Collapses in Greenville, ILMost basement foundation walls—even if they are brick or block walls—can be saved.  The most common cause for foundation walls bowing in is saturated clay soils in the backfill.  This often occurs when gutters are left unattended and rain water spills over them, or downspouts drop right next to the foundation.  Also, improper grading—when the backfill slopes back towards the foundation—funneling water to the foundation can cause this saturated backfill situation.  As the clay soils in the backfill next to the foundation wall gets wet, the soils expand and push the foundation walls in towards the basement.

When this occurs, cracking in the foundation walls occur.  If the wall is poured concrete, the most common type of cracking is diagonal.  The cracks will generally start at the top of the wall, and angle back toward the nearest corner.  If the foundation walls are brick or block, then the more common cracking pattern is a horizontal crack toward the mid part of the wall, then stair step cracking once you get close to the corners. 

When you see these cracks, it’s time to call a professional.  If the problem is caught soon enough, the walls can be stabilized by the installation of a wall restraint system.  These systems could consist of helix style blades attached to square or round steel shafts, advanced through the soil with a hydraulic motor, or threaded rods pushed out through the soil with pneumatic equipment and steel plates connected to both ends.  Another option would be steel I-beams against the walls, with brackets mounted to the concrete floor below and the floor joists above.  Determining the correct system depends on the obstacles to be worked around, and the results you wish to achieve.

Sparta, IL — Poured foundation wall pushed in 18 inches.Sparta, IL — Foundation wall restored with Geo-Lock™ Wall Anchors

 

If the wall is bowed in a great deal, then straightening the wall may be necessary.  In order to straighten a foundation wall, the soil next to the foundation would need to be excavated.  In some instances, this means the removal of patios, decks, A/C units or even utility lines.  After the soil is removed, then one of the above systems can be utilized to straighten the foundation wall.  Once the wall is straightened, the backfill can be replaced and replacement of any other items that were removed can begin.  The down side to this process is that the soil next to the house and out approximately 20 feet gets disturbed by the excavation equipment, and it can take a while for the grass to re-grow.

The question then is: How far is too far, before the wall is too far gone to restrain?  Well, the threaded rod and steel plate system has been used successfully to straighten a poured concrete wall that had bowed in eighteen inches!  With that said, consulting a qualified professional would be the first step in determining what can be done to fix your bowed foundation walls.

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Woods Basement Systems, Inc.
524 Vandalia Street
Collinsville, IL 62234
1-618-708-4055