The Hidden Threat of Kirkland silt loam, 0 to 1 percent slopes for Homeowners in Norman
Geological Profile: Norman, OK
What is Kirkland silt loam, 0 to 1 percent slopes?
Kirkland silt loam, 0 to 1 percent slopes is a moderate clay soil formation common in Norman. It is characterized by a high silica content that causes it to absorb water and swell volume by up to 2.6%. Engineers value it for agriculture but fear it for construction due to its "shrink-swell" volatility.
Why Norman Foundations Fail
If you live in Hall Park, or surrounding areas, your home is interacting with this critical geology. Unlike stable sandy loams, Kirkland clay moves.
The defining metric is the Plasticity Index (PI) of 14.0. This PI indicates relatively stable ground, though localized drainage issues can still undermine grade beams.
The "Active Zone" Depth
In Norman, 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 73072.
- Elias Thorne, Lead Forensic Engineer
3 Signs of Kirkland 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
| Method | Suitability for Kirkland silt loam, 0 to 1 percent slopes | Verdict |
|---|---|---|
| Pressed Concrete Piling | Often shallow (8-10ft); relies on friction in active clay. | Avoid ❌ |
| Steel Piers (E3000) | Driven to absolute refusal (rock/shale) below active zone. | Recommended ✅ |
| Bell-Bottom Piers | Drilled concrete; excellent stability but higher cost/mess. | Viable Option |
Own a home in Norman?
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Neighborhood Watch
We are monitoring elevated PI readings in these areas:
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