Bowing or Buckling Foundation Walls
By the time you've begun to notice bowing or buckling in your basement walls, there’s a good chance that this situation has been present for a long time.
Bowing walls occur most often due to the force of hydrostatic pressure. Hydrostatic pressure occurs when water presses against the basement walls, causing the weight against the walls to exceed their capacity. Walls can also bow and fail when expansive clays or frost cause expansion of the soils to fatigue and damage the wall. Cracking, bowing, and buckling foundations are indicators of a serious problem for a homeowner.
Walls with severe structural damage will show additional horizontal cracks, shearing, and bowing as time progresses, and in some cases, the only way to repair the problem is to completely remove and rebuild the foundation wall.
This process requires quite a bit of work, with the process beginning in your yard. Before the foundation is excavated, the yard around your foundation must be removed. This includes all landscaping such as gardens, steps, walkways, foliage, and everything else located along the foundation. Then the foundation will be excavated, with the removed soil being laid in mounds around the house. Temporary supports will be put in place as the foundation walls are removed and replaced. When the job is completed, the landscaping and dirt can be returned. A year later, this soil will settle and must be regraded.
Although they can be a sign of foundation settlement, vertical cracks in a foundation wall are not necessarily a sign of serious structural damage in your home. Vertical cracks are often caused by the shrinking of concrete as it cures; if the edges of a small crack feel even as you run your fingers along the sides, this is likely the reason why. However, it's always a good idea to have a professional look at the problem, so you can be sure that the problem is not major before it gets much worse.
Horizontal cracks found on foundation walls are indications of a very serious problem, and over time, they can lead to a complete foundation wall failure. Brick walls are just as vulnerable to cracking and bowing as other walls, and they're also susceptible to crumbling mortar.
Poor drainage and grading of soil around a structure can cause water to drain slowly. This water will saturate the ground around the foundation walls, causing an increase in hydrostatic (water) pressure. As the combined forces of hydrostatic pressure and the natural weight of the soils surrounding the foundation bear down, it can exceed the weight-bearing capacity of the walls, causing them to crack, bow, or shear.
When homes have clay soils that expand and contract dramatically with water (known as "expansive clays"), these soils can do even more damage. The lateral pressure against the walls can be as much as several tons per square foot!
It's possible to permanently repair a foundation wall crack. Minor cracks that show no leaking may need only a cosmetic repair, and will not be a problem unless they reoccur. And when it comes to a leaking crack where there is no threat of foundation failure, there have been many innovations in wall crack repair that have made it possible to repair the cracks without high-pressure injection equipment or the need to drill holes in the foundation wall.