Foundations are primarily affected by the soil they’re built on and the weather, both of which cause most of the under-home damages in Wake Forest. We’ll discuss the specific problems present in the city and the surrounding area below.
Expansive Soil
Wake County’s soil has an abundance of clay – specifically red clay –which is known to be highly expansive. The tiny clay particles give expansive soils three primary characteristics that make them dangerous for home foundations.
Clay is absorbent, so clay-rich soil naturally takes in more water than a soil made up of larger sand or silt particles. The clay in the ground in Wake County absorbs runoff readily, gradually increasing in size as it takes in more water.
Moisture causes the ground to swell, which leads to the expanding soil pressing against your foundation with more force than it typically does. The added stress can compromise the structural integrity of your concrete slab or foundation walls. Structural damage is possible if the excess hydrostatic pressure isn’t relieved.
Clay is not only absorbent, but it retains water more than other soil constituents. Following rainfall in Wake Forest, the ground holds runoff for long periods, exposing your foundation to moisture constantly until it dries.
The longer water in the soil is exposed to your home’s foundation, the greater the chance of it leaking through foundation cracks or concrete pores.
Unfortunately, the hydrostatic pressure created by the swelling soil also forces moisture against your concrete with intense pressure, further increasing the likelihood of it seeping inside. Water damage and moisture accumulation are both severe threats to the concrete under your home.
Finally, expansive soil is most problematic in Wake Forest when it’s wet, but it can also necessitate structural repair if it dries. The volume that the soil gains when it absorbs water is lost in equal proportions when the moisture dissipates through drainage or evaporation. The shrinking soil pulls away from your concrete, which in turn sinks to maintain contact and support.
The potential for damage occurs when the drying process happens unevenly under your structure. Differential settling can create enough stress to cause your slab to crack, leaving you with costly structural damage and the potential for foundation failure.
Above-Average Rainfall
The problems with expansive soil are most prevalent when the ground remains wet or when the moisture content fluctuates. Unfortunately, the weather patterns in Wake Forest contribute to both issues.
The city receives over 46 inches of rain annually, which is about one and a half times the national average. The summer months bring the most abundant rain, with some months reaching double the monthly average of others throughout the year.

The above-average precipitation can cause flooding and excess moisture in the ground, both of which promote groundswell and the associated hydrostatic pressure on your concrete foundation.
Additionally, rainfall occurs frequently, especially in the summer months. As such, water intrusion is a widespread problem in the area, given that your foundation will continuously be in contact with moisture during the wetter months.
Multi-Level Foundations
The Research Triangle and many other developed areas throughout North Carolina have an abundance of multi-level foundations, such as partial basements and cellars.
Multi-level foundations are a design choice that occurs sporadically throughout the United States, but it’s prevalent in the Raleigh area specifically.
Multi-level foundations have two slabs, one sitting near the surface and one lying well below the first, often at a depth of over 7 feet. These foundations often lead to differential settlement because the ground dries at different rates depending on the depth.
This is especially true in Wake Forest, where clay soil is present, as water passes very slowly through the ground.
The result of uneven drying and shrinking is varying support beneath your foundation. Eventually, the inconsistent support can crack your concrete, causing severe structural damages.
High, Year-Round Humidity
Finally, Wake Forest residents contend with high year-round humidity, usually between 60% and 70% regardless of the season. Crawlspaces and basements are naturally prone to moisture accumulation, and the humid air in Wake Forest elevates the potential for a problem.
The humidity from outside can get trapped beneath your house, leaving consistently damp air in your under-home area.
Moisture can promote mold growth and damage to construction material, and it can seep upstairs to your living space and compromise your air quality.