Digging close to the foundation. As a rule of thumb, the depth of a hole should be no greater than the distance to the foundation. Removing soil close to a foundation can cause a slumping, or a landslide condition. You often see this situation along new highways that cut through hills with steep enbankments.
Inadequate drainage. Pooling water will turn the supportive soil into mud. Even when the pool disappears after an hour or so, the damage continues below the surface of the ground.
Gutter problems: The absence of gutters can lead to a ground depression along the drip line, which collects an inordinate amount of water caused by improper drainage. Gutter downspouts need to be extended at least 3 feet away from the house to prevent a massive flood at the foundation perimeter.
Plumbing leaks: Leaks can cause soil to swell, lifting the house off of piers. Leaks will also carry away soil that supports the house, and may drip down along the supporting piers, causing the base of the pier to slip into mud.
House remodeling: Adding a second story or fireplace or any other change which increases the load upon the piers may cause the piers to sink. Piers are normally spaced in accordance with the expected load. Adding house weight may require that additional piers be installed.
Stream beds: The Dallas area used to have many more rolling hills and streams than are apparent today. Builders have filled the streams with loosely compacted soil. The stream bed can remain active, even though subterranean, and erode soil under a pier.
Inadequate watering or over watering: Inadequate watering allows the soil to shrink away from a foundation, while over watering causes the soil under a foundation to turn to mud. Both situations put excessive loading on the piers.
Soaker hoses: These are fine when placed 12-18 inches from the slab. When placed closer, the water pours down along the side of the perimeter beam, turning soil at the base of the foundation perimeter beam to mud and putting undue stress on the area of foundation repair.
General Erosion: This may be caused by poor drainage, or by a plumbing leak in a neighbor’s house, or a change to landscaping which alters the flow of water.
Trees: Trees should be planted at least 1/2 the height of their mature canopy away from foundation. Plant the trees closer and during periods of drought the roots will suck moisture from under the house, causing soil slumping and creating the need for foundation repair.