There are a few factors that create issues in the North Carolina Triad, each often resulting in a different type of foundation damage. We’ll discuss each of these factors in-depth below.
Expansive Soil
One of the most widespread factors that causes foundation damage throughout the country is expansive soil. Expansive soil grows in volume when it gets wet and shrinks when it dries, sometimes creating excessive ground movement that can be detrimental to foundations.
There’s an arc of exotic soil in North Carolina believed to have been deposited by glaciers several hundred million years ago. The two distinct soil patterns are referred to as the
Triassic basin and the Carolina terrane, the latter of which covers most of Guilford County. The soil in this region has a high concentration of clay, making it a highly expansive soil. This presents three significant risks for foundations in Greensboro.
First, clay soil absorbs runoff readily and expands when it gets wet. It can increase in volume up to about 10%, putting excess pressure on your foundation walls. The stress can cause inward wall movement and even collapse.
Second, expansive soil loses volume when it dries. If too much water in the ground evaporates or drains, the soil can shrink away from your foundation and leave it unsupported. This often occurs around the edges of your property and can cause differential settling, causing portions of your home to sink into the ground more rapidly than others.
Lastly, the clay in Greensboro dirt holds moisture for more extended periods than non-expansive soil. When runoff is held against your concrete, it can seep in through settling cracks or wick through solid concrete and enter your home.
Above-Average Rainfall & Drought
Greensboro and much of North Carolina experiences almost 45 inches of rain annually, nearly 50% higher than the national average. Water and foundations don’t mix well, so the above-average amount of precipitation in Greensboro can create severe issues for homeowners. Excessive runoff not only damages concrete over time as it freezes, but it can easily seep into your crawlspace or basement and create moisture build-up inside.

While rainfall can be a problem, a lack of it can be even worse. Northern parts of North Carolina are prone to drought, which dries the soil and can cause dangerous differential settling. Sections of concrete can be left unsupported by the earth, eventually leading to the cracking and sinking of your foundation.
Rainfall and drought can damage foundations anywhere in the country. However, the combination of these issues with expansive soil in the Carolina terrane increases the potential for water damage and foundation problems for Greensboro property owners.
Multi-Level Foundations
Some Greensboro residents have full basements or crawlspaces, but unlike many other parts of the country, multi-level foundations are also standard. The split design is convenient and far cheaper to install than a full basement, but it leaves your home more prone to foundation problems.
The issue arises because your concrete is supported by soil at varying depths. Ground settling depends mainly on the water content in the earth, so the moisture levels can vary significantly under different parts of your house. As such, differential settling can cause sinking foundations, cracking, and loss of structural integrity.
Once again, the inherent issues with multi-level foundations are compounded by the presence of expansive soil, posing an additional risk for homeowners in Greensboro.
High Humidity
Lastly, Greensboro experiences an average humidity of around 75%, with a relatively high dew point as well. This combination means the air can – and regularly does – hold an above-average amount of moisture.
Moisture can be a problem in any part of the home, but basements and crawlspaces are especially prone to moisture build-up. Elevated humidity under your house can stimulate mold growth, attract pests like termites and rodents, and damage building material like floor joists and framing over time.
The expansive soil can contribute to humidity in your basement or crawlspace, as it can hold water against your concrete and force water inside via hydrostatic pressure on your basement walls.