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Foundation Repair
- By Martin Dawson
- Published 01/9/2010
- General
Martin Dawson
Martin Dawson is the co-founder of Dawson Foundation Repair headquartered in Houston, Texas. He is a leading authority on repairing failed commercial and home foundations using the time tested and thoroughly researched drilled Bell Bottom Pier method. His company has serviced Texas and other southern states since 1984.
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Residential and small commercial properties often have a need for foundation repair. This is because the concrete slab foundation experiences movement and settlement problems. And the resulting damage to the building structure can be severe and include loss of real estate value. There are a host of problems that can result from foundation movement and settlement including unsightly cracks in walls, cracks in floors, tripping hazards, potential accidents, poor drainage, and equipment malfunctions.
There are a number of visual signs with the building structure that will indicate a need for foundation repair. The most common signs inside a building structure are floors that are not level or cracked, separation or gaps between walls and floors or windows, windows that will not open or close easily because the frame is no longer square, doors that do not open or close properly, cracks in sheetrock, and nails that are being “pushed out” of sheetrock. In addition, there are a number of visual signs on the outside of the building structure that could indicate a need for repair. These outside signs include vertical and stair-step cracks in the brick, separation or gaps between the bricks and doors or windows, sagging roof, and any part of the house that appears to be separating or leaning in the wrong direction.
The need for foundation repair usually is caused by one or more factors. These factors include expansive soils underneath the foundation, improperly compacted soil underneath the foundation, and improper maintenance around foundations. The first factor, expansive soils, is probably the most common cause of foundation movement and settlement. Certain soils, such as clays, will absorb water like a sponge. When the weather is hot and dry these soils will then lose the water due to evaporation. When these soils are absorbing and then losing water, their volume is expanding and contracting. All of this soil movement is transferred to the structure’s foundation. When the soil expands the foundation is moved upward. When the soil contracts, the foundation above it loses contact with the soil and therefore has lost its support. The foundation will tend to “fall down” at this point. Of course, if the soil expanded and contracted in a uniform manner then the foundation would have uniform support and be free of problems. However, that does not happen in the real world. What does happen is that the soil under one area of the foundation is exposed to more water absorption and/or water contraction than other areas. This causes one part of the foundation and the structure to move upward and then downward while other parts remain relatively stable. Typically, the edges of a foundation are far more exposed to soil/water absorption and soil/water contraction than the interior of the foundation. The soil underneath the center of the foundation tends to remain relatively stable unless it is exposed to large volumes of water from plumbing leaks or poor drainage.
Building structures may need foundation repair if the soil underneath the foundation has been improperly compacted prior to the pouring of the foundation’s concrete. Typically this means that the soil is “too loose” and will tend to compact itself over time. Water will accelerate this compaction process and it frequently does. The water may arrive via plumbing leaks or rain. When the soil becomes compacted it loses contact with the bottom of the concrete slab foundation. The foundation now has nothing to support it and if the forces are great enough the foundation will “fall in” or “cave in” in the area where there is no support.
Foundation repair may be necessary if the foundation has not been maintained properly. Water movement, and the resulting expansion and contraction of the soil, must be properly handled. Poor drainage can lead to an excess of water in one location of the foundation and create excess expansion and upward movement in this area. Also, large trees and shrubs can draw a large amount of water from an area under the foundation. If this is allowed to happen then this area of the foundation will have excess water withdrawal and therefore excess soil contraction. If the soil contracts too much, it loses contact with the foundation and the foundation in this area has no support underneath and will tend to sink or “fall in.”
There are a number of visual signs with the building structure that will indicate a need for foundation repair. The most common signs inside a building structure are floors that are not level or cracked, separation or gaps between walls and floors or windows, windows that will not open or close easily because the frame is no longer square, doors that do not open or close properly, cracks in sheetrock, and nails that are being “pushed out” of sheetrock. In addition, there are a number of visual signs on the outside of the building structure that could indicate a need for repair. These outside signs include vertical and stair-step cracks in the brick, separation or gaps between the bricks and doors or windows, sagging roof, and any part of the house that appears to be separating or leaning in the wrong direction.
The need for foundation repair usually is caused by one or more factors. These factors include expansive soils underneath the foundation, improperly compacted soil underneath the foundation, and improper maintenance around foundations. The first factor, expansive soils, is probably the most common cause of foundation movement and settlement. Certain soils, such as clays, will absorb water like a sponge. When the weather is hot and dry these soils will then lose the water due to evaporation. When these soils are absorbing and then losing water, their volume is expanding and contracting. All of this soil movement is transferred to the structure’s foundation. When the soil expands the foundation is moved upward. When the soil contracts, the foundation above it loses contact with the soil and therefore has lost its support. The foundation will tend to “fall down” at this point. Of course, if the soil expanded and contracted in a uniform manner then the foundation would have uniform support and be free of problems. However, that does not happen in the real world. What does happen is that the soil under one area of the foundation is exposed to more water absorption and/or water contraction than other areas. This causes one part of the foundation and the structure to move upward and then downward while other parts remain relatively stable. Typically, the edges of a foundation are far more exposed to soil/water absorption and soil/water contraction than the interior of the foundation. The soil underneath the center of the foundation tends to remain relatively stable unless it is exposed to large volumes of water from plumbing leaks or poor drainage.
Building structures may need foundation repair if the soil underneath the foundation has been improperly compacted prior to the pouring of the foundation’s concrete. Typically this means that the soil is “too loose” and will tend to compact itself over time. Water will accelerate this compaction process and it frequently does. The water may arrive via plumbing leaks or rain. When the soil becomes compacted it loses contact with the bottom of the concrete slab foundation. The foundation now has nothing to support it and if the forces are great enough the foundation will “fall in” or “cave in” in the area where there is no support.
Foundation repair may be necessary if the foundation has not been maintained properly. Water movement, and the resulting expansion and contraction of the soil, must be properly handled. Poor drainage can lead to an excess of water in one location of the foundation and create excess expansion and upward movement in this area. Also, large trees and shrubs can draw a large amount of water from an area under the foundation. If this is allowed to happen then this area of the foundation will have excess water withdrawal and therefore excess soil contraction. If the soil contracts too much, it loses contact with the foundation and the foundation in this area has no support underneath and will tend to sink or “fall in.”
