While Fresno’s a great place to live, the city presents some unique challenges for your home’s structural integrity. Many homes in Fresno are built on a concrete slab foundation, a popular option throughout California because it remains more stable in an earthquake. Basements and crawl spaces are less common, but some homes built before the 1970s will have them. Regardless of the type of home you live in, the natural properties of this region are the causes of foundation damage in Fresno. That includes the soil, the weather, and even our proximity to the San Andreas Fault.
Expansive Soil
Did you know California has an official “state soil”? It’s called San Joaquin, and we have plenty of it in Fresno. This loamy soil is a combination of silt, sand, and clay. Soils that contain clay are known to be highly expansive because they naturally absorb a lot of water. This expansive quality makes them prone to swell up substantially when there’s a lot of moisture and then shrink back down just as substantially during drier conditions. Foundations are susceptible to the surrounding soil’s behavior, which makes expansive soils such a challenge for the structural integrity of homes. Your foundation tends to shift in response to the soil’s movements, especially as it cycles through the extreme moisture changes in Fresno’s climate. We only get around 11 inches of rain each year, making this region pretty close to a desert. Most of the rain falls during the winter months, leaving drought-like conditions for long stretches of the year.
Concrete slab foundations are specifically susceptible to damage from upheaval, which is when the soil underneath swells up with water and causes cracks. Overall, the fluctuations of expansive soil cause a lot of wear and tear for any type of foundation.
Earthquakes
The San Joaquin Valley is in a pretty sheltered part of California, geologically speaking. We haven’t seen a severe earthquake for almost 40 years. However, we’re still firmly in earthquake country and only a little over 100 miles from the San Andreas Fault. That means homeowners in Fresno do have to contend with plenty of seismic action. The earthquakes in our region are only between 1 and 4 on the Richter scale, but they happen several times per month. The cumulative effect of even relatively mild earthquakes is simply not good for your foundation. Concrete slab foundations will do better, but they’re not immune to earthquake-related stress. Any time that the ground is shifting beneath your home, there’s a possibility of some damage.
Seismic activity can also worsen any existing foundation problems, such as minor cracks that weren’t posing an issue yet. The seismic activity is one primary reason why Fresno homeowners need to stay mindful of the state of their home’s foundation and pay attention to warning signs of potential issues.
Tree Roots
Fresno’s trees add so much beauty to the landscape, but they can also be a potential threat to your home’s stability. The problem is specifically with native large trees like the Valley Oak, one of the largest oak trees known for having a massive root system. The roots of this Fresno native can extend outwards by over 30 feet in their search for water and nutrients. These amazing roots have a lot to do with why the Valley Oak can thrive in a semi-desert environment. But, as many Fresno homeowners have learned the hard way, these roots can also exert plenty of force on your foundation walls. If they can grow into any minor cracks in the foundation, tree roots can easily cause them to widen.
It’s also common for large trees to become a disruptive influence on the surrounding soil by sucking up moisture and creating uneven shrinkage beneath your foundation. In short, Valley Oaks are a magnificent sight, but they should never be too close to your home. Any trees that are currently too close for comfort should be professionally removed or, if possible, transplanted to a better location.