What Is Soil Washout?

Soil washout happens when flowing water erodes and carries away the topsoil. This form of rapid erosion often occurs on sloped or uneven terrain, especially in higher-elevation areas of the Carolinas.

On residential properties, even small daily activities, such as walking across the yard or watering plants, can cause minor soil movement, known as splash erosion. In humid regions like South Carolina, Western North Carolina, and Georgia, frequent rainfall and varied soil types intensify this process, often washing soil from beneath concrete slabs and foundations.

Because most lawns and yards naturally slope or shift over time, even moderate rainfall can lead to erosion around your foundation. Storms, drainage issues, and landscape changes further worsen washout by redirecting surface water.

Your Property’s Terrain

The Appalachian Mountains and surrounding foothills make the soil and terrain across North and South Carolina more sensitive to erosion than in flatter regions. Homes built on slopes or uneven ground experience natural runoff during rain, which gradually washes away topsoil. Over time, this movement destabilizes the ground beneath your concrete and foundation, increasing the risk of cracking and settlement.

Excess Precipitation

Frequent rainfall, storms, and rapid snowmelt can all contribute to soil washout. When heavy precipitation saturates the ground, water carries fine soil particles away from beneath concrete slabs and foundations. Even small, repeated washouts can create voids that worsen with ongoing rain or flooding, eventually leading to uneven or sinking concrete.

Inadequate Drainage

Poor grading and inadequate drainage systems, such as missing or misdirected gutters and downspouts, allow water to pool near your foundation. This standing water increases hydrostatic pressure and accelerates erosion around concrete structures. Ensuring proper yard grading and directing runoff away from your home are essential steps in preventing soil washout and foundation damage.

Fixing soil erosion beneath concrete begins with identifying and correcting the source of the problem, typically poor drainage or uncontrolled water flow. Inspect your property’s grading, gutters, and downspouts to ensure water is directed away from your home’s foundation and concrete surfaces.

After addressing drainage issues, fill voids and stabilize the underlying soil with polyurethane foam injection (PolyRenewal™). This process involves injecting a high-density, eco-friendly foam beneath the affected slab to lift the sunken concrete back into place. Polyurethane cures quickly, provides long-term support, and prevents future washout. This solution allows for same-day use of the treated areas.

Are there cracks or uneven concrete surfaces on your property? Mount Valley Foundation Services can help. 

Our local experts repair concrete and stabilize foundations affected by Carolina soil conditions. Schedule your free inspection today to identify the cause and prevent further damage to your property.