Top 5 Causes of Adverse Foundation Movement

Many homes are built on old wooded areas, filled land, or inadequately compacted soils. When the underlying soils vary in density or history, different parts of the slab respond differently to moisture.

This creates differential movement from day one — before the home even experiences its first summer drought.

Inconsistent watering keeps clay in a chronically shrunken state. Edges and long walls suffer the most.

Whole-yard irrigation is more effective than limited “foundation watering” because it keeps the soil cycling more evenly.

Missing gutters, front-only gutters, or negative grading create saturated zones while other areas dry out.

Slabs bend when one side swells and the other contracts. This is one of the most overlooked causes of differential movement.

Oak roots can extend up to 3× the canopy radius, quietly extracting moisture from the clay within their zone of influence.

Without a properly installed root barrier, this creates localized shrinkage — one of the fastest ways to create asymmetrical foundation movement.

The #1 cause that surprises almost every homeowner: prior foundation repairs can create new foundation problems.

Traditional piles and piers are static supports installed in a soil system that constantly expands and contracts. Once part of a slab is pinned, the remaining areas continue cycling alone — leading to bending, distortion, and in many cases, the dreaded interior settlement.

This is why Pier-less advocates an Earth-First approach — stabilizing the soil before considering invasive underpinning.

While not included in the Top 5, below-ground plumbing leaks deserve special mention because they can dramatically affect how a foundation behaves—especially on Houston’s expansive clay soils.

When a supply or drain line leaks beneath the slab, the surrounding clay absorbs and retains water, causing it to swell, lift, and heave. This can create upward distortion that mimics or amplifies foundation movement. In severe cases, the slab may rise several fractions of an inch in a localized area, creating new cracks, door misalignment, or floor slope that wasn’t present before.

However, it’s important to understand that plumbing leaks are usually a side effect—not the original cause—of foundation movement. Excessive downward or upward soil movement can strain or fracture pipes.

Additionally, previous foundation repairs—especially aggressive perimeter lifting—can contribute to plumbing damage when portions of the slab are raised while the plumbing system remains rigid and interconnected beneath the home.

For that reason, below-ground plumbing issues are not listed as one of the top causes of adverse foundation movement, but rather as a secondary condition that often develops after movement has already occurred. Still, it remains a critical factor to evaluate when diagnosing foundation performance.