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Drainage and Moisture Management

“Water is our best friend, and our worst enemy.”

Inadequate Drainage Inadequate drainage occurs when the topography is flat, slopes toward the house, or puddles near inside closed planters. When irrigation volume is unnecessarily high, or torrential rains occur, this creates ‘ponding’ conditions. Common scenarios include:

• Yard drains blocked due to debris or lack of maintenance.

• Rain gutters draining directly adjacent to the foundation, often into a planter that creates pooling.

• Excessive use of the hose along a backyard wall.

Seasonal Moisture Fluctuations

• Extreme Winters: Excess moisture can cause upward heaving of foundations as volume increases, but can also cause rapid settlement when soil becomes unable to support the load.

• Hot Summers/Drought: Downward foundation settlement can occur as moisture volume decreases and soil becomes more compressible.

• Soil Elevation Changes: Loamy soil can experience elevation changes of up to four inches simply due to the loss of volume.

• Optimal Moisture: Maintaining an optimal range of moisture is the key to keeping your foundation in good health.

Soil Properties and Classification

The Plasticity Index (PI) The plasticity index (PI) is a measure of the plasticity of a soil. A higher PI indicates a greater potential for foundation problems.

Soil Types

• Sandy Soil: Consists of small particles of weathered rock. It has very low nutrients and poor water holding capacity. Usually experiences little settlement.

• Silty Soil: Smaller particles than sand; holds water better. Often found in lowland valleys near natural water flows or lakes.

• Loamy Soil: A combination of sand, silt, and clay that includes humus. It has a high probability of soil consolidation.

• Clay (Clayey Soil): Particles are tightly packed with little airspace. Clay has a high expansion and contraction rate. It causes more damage to residential structures across the U.S. yearly than Hurricane Katrina and Sandy combined.

Identifying Foundation Problems

Visual Warning Signs

• Cracked walls (especially in corners or the ceiling).

• Stuck doors or windows that will no longer open or latch.

• Sinking floors or a crooked roof line.

• Leaning chimneys.

• Vertical cracks in the foundation.

• Counters and cabinets pulling away from the wall.

• Cracks forming in counter-tops.

Questions for Assessment When inspecting your home, consider these four key questions:

1. When did the settlement or cracking occur?

2. Is the problem getting worse?

3. Did you stop the cause, or is the cause ongoing and getting worse over time?

4. How long are you willing to wait until the problem gets bad enough to finally call a professional?