What Are the Causes of a Foundation Settling?

Weak Soil

• Weak soil will not support a substantial structure, and the soil will collapse and compact down under the weight of the home. General guideline footings installed on a foundation will rapidly sink, and the foundation will suffer damage. If the builder suspects the site suffers from weak soil, he can elect to build the home on site-specific footings to help spread the weight of the house over a larger area. A footing is the lower part of the foundation that sits against the soil. Specially designed site-specific footings will rest better on weak soil and may not settle. Laying fill soil down in an area that suffers from weak soil will also help prevent a foundation from settling.

Moisture and Drought

• A home built in an area with heavy rain and flooding may also settle when the soil becomes compacted from water saturation. Overly saturated soil occurs from rainfall, a broken water pipe, raised groundwater and poor site drainage. In addition, clay soil expands when wet, but shrinks when dry. If the soil suffers excessive drought conditions, it will shrink beneath the foundation, which will cause settling.

Trees and Vegetation

• Large trees and abundant vegetation will cause a home's foundation to settle and sustain damage. Tree and plant roots often grow close to the soil's surface. They will heave the soil up and cause it to sink in other locations. Also, the tree's roots will make the soil overly dry beneath the foundation. The homeowner should avoid planting trees near the home. If a large tree begins to cause damage to the home, it may require removal.

Prevention

• A settling foundation from soil problems usually occurs a few years after the home's construction. It may take many years for a foundation to experience settling as a result of large tree roots or abundant vegetation. A homeowner can help prevent a home from settling in a drought by moistening the soil around the house. Avoid saturating the soil when watering, however. Moisten only the top 1 to 2 inches of soil once per week during times of drought. Also, water should never pool around the foundation.