There are a variety of foundation types in Sacramento and the surrounding area. While there are not a lot, there are some older homes that have full basements. Most houses here either have a crawlspace or slab foundation. There are benefits to each and there are potential problems, too.
Crawlspace foundations are built with footings and block walls around the outside perimeter of the house. This allows for airflow under the home and prevents moisture buildup which, generally, is not a problem in Sacramento. As the name implies, a slab foundation is made of one solid slab of concrete. This type of foundation is often used in areas, such as Sacramento, that do not suffer from freezing temperatures followed by thawing which could, in time, harm the cement.
People who live in any place that experiences earthquakes know firsthand what damage the earth’s movement can do. From relatively minor issues, such as cupboard contents hitting the floor and loose bricks falling from chimneys, to more extensive structural damage or electrical issues breaking out into fires, earthquakes can leave homes and their owners shaken.
The earth’s movement is also trying on the foundation of any building, including houses. Depending on the relative location of an earthquake to your home, its severity, and how the earth’s plates shifted during the quake, it can have major effects on your foundation, causing cracking and, in some cases, support failure.
Many foundation problems result from a shifting of the soil underneath the foundation itself. That is often caused by hydrostatic pressure, a result of the groundwater levels affecting the soil, which changes from season to season. In a wet winter, the soil absorbs more water causing the pressure to increase resulting in pressure against the foundation itself. That can cause the foundation to shift and crack.
If trees are growing close to the house, their root structures can become a problem as they grow. The roots expand outward from the tree and increase in diameter. Many think that an older tree has deeper roots. That is not always true. Either way, the roots can affect the surrounding soil and can affect the foundation itself.
With continued water levels changing seasonally, and year after year, from mild rains to heavy rains and subsequent dry spells, the soil will erode. This will not only settle a foundation, but can sink it unevenly in some places. In some cases, the soil may not have been compacted well before construction, which can add to foundation failure.