The Hidden Threat of Evanston loam, 1 to 6 percent slopes for Homeowners in Gypsum

What is Evanston loam, 1 to 6 percent slopes?

Evanston loam, 1 to 6 percent slopes is a moderate clay soil formation common in Gypsum. It is characterized by a high silica content that causes it to absorb water and swell volume by up to 1.5%. Engineers value it for agriculture but fear it for construction due to its "shrink-swell" volatility.

Why Gypsum Foundations Fail

If you live in Central Gypsum, or surrounding areas, your home is interacting with this critical geology. Unlike stable sandy loams, Evanston clay moves. Because of this severe movement, homeowners experiencing active structural settlement should immediately consult our Gypsum Foundation Repair engineering team.

The defining metric is the Plasticity Index (PI) of 7.5. This PI indicates relatively stable ground, though localized drainage issues can still undermine grade beams.

The "Active Zone" Depth

In Gypsum, the "Active Zone"—where moisture levels fluctuate—extends 12-15 feet deep. Standard builder piers often stop at 8 feet. This mismatch is why we see repetitive failures in 00000.

3 Signs of Evanston Soil Failure

• Diagonal Shear Cracks: Extending from door/window corners (45-degree angles).
• Friable Soil Gap: Soil pulling 1-2 inches away from the foundation perimeter in summer.
• Sticking Doors: Specifically on the exterior walls relative to the center of the home.

Engineering Protocol: Correct vs. Incorrect

Neighborhood Watch

We are monitoring elevated PI readings in these areas: