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Tuesday, July 12, 2011

What Causes Basement Wall Failure?


Improper Drainage

Poor slope or drainage around a building causes surface water to drain away slowly, thereby increasing water infiltration next to the foundation.  Increased soil moisture conditions increase hydrostatic (water) pressures on basement walls.  If the combined hydrostatic pressure and earth pressure (pressure exerted by the surrounding soil) on the wall exceed the wall's design capacity, the wall will crack, bow, lean, or shear.

Expansive Clays

Clay soils are considered expansive when they have the capacity for extreme volume changes with fluctuations in water content.  In short, expansive clays swell when wetted and shrink when dried.  Expansive, swelling clays against basement walls can exert lateral pressures on the walls of the magnitude of several tons per square foot! 

Foundation Wall Cracks

Foundation wall cracks can easily get worse if they're left untreated, especially in the case of cinder block wall foundations.  Any crack or opening in the foundation at all can become a passageway for water to enter into the home.  Additionally, because the foundation wall is literally cracked through, the gap will continue to worsen as the walls move and become influenced by pressure from outside the walls.  One crack in the foundation walls will lead to another, and no crack will ever improve on its own.  All cracks should be repaired if they're allowing water through, and even a hairline crack can be evidence of a larger problem and should be inspected by a professional immediately.
Soil Pressure

Horizontal Foundation Wall Cracks

Horizontal foundation wall cracks are potentially very serious problems that can sometimes lead to the complete failure of the foundation walls. These cracks occur when pressure builds against the side walls and forces them inwards. Given time, this pressure can snap the walls, creating an enormous and devastating problem. If you detect any crack like this, you should call Foundation Supportworks for a free foundation estimate. Many options are available for all foundation problems such as wall anchors, and crawl space support beams that will competently repair your wall, contribute strength, and help prevent the inward movement of the walls, redistributing the weight to where the load can be better handled.

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