Diagnosing Causes of Horizontal Foundation Cracks
Horizontal foundation crack patterns are usually the result of pressure from outside soils, and there is almost always at least a slight bow to the wall as evidence of that pressure, but not always. Sometimes that pressure can come from one event, such as temporary swelling of the soil from a flood. The pressure can also come from vehicle movement outside the wall, swelling soil from improper drainage or freezing. Often, a combination of factors is contributing to the problem.
Horizontal foundation cracks that are located high on a wall are usually a sign of vehicle loading or surface water pressure and frost. The latter is true mostly in northern climates subject to frost and may be located near the frost line. If you suspect frost damage, look for signs of water accumulation outside and near the wall showing the crack.
Horizontal foundation cracks that are located at mid-wall height could also be a result of vehicle loading, either because of a driveway close by or some history of heavy equipment moving nearby. Other likely causes however can be pressure from soils on a hillside or excessive expansion of soil due to moisture. This can be exacerbated by frost.
When the horizontal foundation cracks are lower on a wall, then this is most often an indication of soil pressure. Soil pressure tends to increase lower in the soil.
Common effective stabilizing methods for horizontal foundation cracks include wall anchors, helical wall anchors, and carbon fiber straps to stabilize the movement. Kevlar neck ties might also be used to anchor the foundation wall better to the floor joists, stabilizing leaning and tipping. Another repair method sometime used is to actually reinforce the walls with steel beams.
In certain extreme cases, damage is so great that the foundation is permanently destabilized and must be replaced. In all cases, the cause of the damage must be addressed, reducing the pressure on the wall to prevent further damage. Have a recommended and qualified inspector walk with you around your home and help you determine your best course of action. |
