Five Questions Answered About Expansive Soils
Updated: Mar 9
Expansive soil causes more damage annually than earthquakes, hurricanes, and floods combined. Avoid serious impact on your home by learning the answers to these five questions.
1. What Is Expansive Soil?
Nearly all clay soils swell when they get wet and shrink when they get dry. Clay soil that swells to extremes is called “expansive soil.” The swelling can occur over a long period of time—weeks, months or even years. Therefore, even if the source of wetting is removed, heaving can occur for a long time afterwards.
2. What Problems Does It Cause?
Swelling will initially occur near the outer edges of a building. The result is a phenomenon called “edge lift.” As landscaping matures water lessens on the outer edges and concentrates under the center of the building. This results in “center lift” to the building. Over time, the lifting at the edges and center of a structure can cause severe geotechnical distress.
3. What Are Some Symptoms of Expanding Soil?
Usual symptoms include doors that will not close properly or stick when they are opened, cabinet doors that will not stay shut, windows that are hard to open and close, diagonal cracks in the wall at the corners of doors and windows— both inside and outside the building, and unlevel floors. Other indicators are gaps above the kitchen cabinets, gaps between the garage door and the concrete driveway on either side, and spaces at the corners of fascia trim. Slab cracks greater than 4 inches and cracks in perimeter walls are also indicators of geotechnical distress.
4. How Can Expansive Soil Problems Be Avoided?
There are several ways to avoid foundation movement due to expansive soils. Here are a few.
• Stabilize Moisture Conditions
One of the most important actions is to ensure that the soil moisture conditions remain relatively constant. Thus, a well-planned, conservative landscape watering program is a simple but important way of controlling differential soils movement.
• Avoid Flooding
Avoid watering shrubs, bushes or flowers planted close to the foundation by “flooding” the planting bed. Trees should not be planted close to the perimeter of the building.
• Maintain Positive Water Flow
Positive water flow away from the building foundation should be maintained to ensure that water readily flows away from the building and does not pond adjacent to or against the building. Care should be taken to ensure that roof runoff water is discharged through downspouts sufficiently distant from the building.
5. What Should I Do If I Suspect Expansive Soil Damage?
If you feel uncomfortable with any of the cracking or other soil-movement-related types of damages, the best solution is to ask a registered professional structural or geotechnical engineer to look at the damage. Not all engineers perform damage investigations, but some specialize in such investigations. If the engineer you contact does not perform damage investigation, you should ask him for the name of an engineer who does.
If you think you have potential construction defects, contact Burdman Law Group for a free, no obligation inspection with a licensed contractor.
This material is for informational purposes only, and is not legal advice. For specific legal advice concerning a particular fact situation, please consult an attorney.