Differential Foundation Movement

Differential Foundation Movement

Problems with residential site design, engineering, and construction may cause uneven settling of the soil.
Long after receipt of the keys at closing, it may plague the homeowner.

The Curse of Differential Settlement

In our part of the state, many residential foundations are subject to uneven settling, or commonly referred to as differential settlement. The pace at which soil settles is often vital. Sometimes, differential foundation movement only requires simple monitoring. By contrast, more rapid settling may immediately threaten the structural integrity of a home. In such a situation, the input of a structural engineer is vital. Timely intervention protects the value of the property.

Signs of Differential Foundation Movement

Differential foundation movement may be more immediate or long-term. Here are some common symptoms:

  • Foundation cracks
  • Window and/or door frames out-of-square
  • Patios, adjacent concrete slabs or outside stairs don’t align
  • Drywall seams open up
  • Chimneys tilt
  • Floors not level

Symptoms and Causes

There are numerous reasons for differential foundation movement. The soil on the site may be:

Insufficiently compacted

Sometimes, the soil itself is fine, but it is not compacted enough during construction. Careless excavation
or site leveling may be at fault. Uneven settling puts the foundation and/or home at risk.

Prone to excess consolidation

The region’s clay soils are often subject to excess compression. The sheer weight of a structure squeezes residual moisture out. Parts of the foundation drop, resulting in serious cracks or other structural damage.

Too wet or dry

Differential foundation movement may also happen when the surrounding and supporting soil gets either too wet or too dry. Saturated soils may lose significant load-bearing capacity. Extremely dry soil shrinks. Either scenario may lead to uneven foundation settling.  A drought.gov graph illustrates the cyclical nature of TX droughts over the past two decades. Wet-dry cycles stress many North Texas foundations.

Adversely impacted by trees or other vegetation

Sometimes, the root systems of nearby trees and other vegetation draw moisture out of the soil, causing it to shrink. Shallow foundations are particularly vulnerable when this happens.

Curing and Preventing Differential Settlement

It is the job of a structural engineer to analyze differential foundation movement and to come up with solutions that area contractors can carry out. Early diagnosis is important. First, it affords an opportunity to solve issues in less costly ways. Second, it allows for timely claims if a home’s designers or contractors are at fault. Years later, it’s often difficult to link problems to improper construction.

Recommendations vary. Monitoring the situation may be all that’s necessary. Special cement patches superficial cracks or gaps. On the other hand, serious differential movement may require significant remedial action. When expansive clay or silt-laden soils cause undue pressure on foundations, replacement with non-expansive soils is one solution.

Contact Us Today

When you observe or suspect foundation problems, call CCM Engineering for a prompt foundation analysis. An expert foundation inspection will yield the answers and the peace of mind you desire. To schedule a professional inspection, please call us anytime at 972.691.6633. Or, contact us online.