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Forensic Soil Report

The Hidden Threat of Contine clay loam for Homeowners in Gilbert

Forensic LeadElias Thorne, P.E.
PublishedAugust 7, 2026
VerifiedGeological Registry v2026.1

Geological Profile: Gilbert, AZ

Soil TypeContine
Plasticity (PI)20.0
Expansion Potential7.5% LEP
Risk ClassMODERATE

What is Contine clay loam?

Contine clay loam is a moderate clay soil formation common in Gilbert. It is characterized by a high silica content that causes it to absorb water and swell volume by up to 7.5%. Engineers value it for agriculture but fear it for construction due to its "shrink-swell" volatility.

Why Gilbert Foundations Fail

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

The defining metric is the Plasticity Index (PI) of 20.0. A PI between 15 and 25 indicates "Moderate" volatility. While not immediate, seasonal neglect (lack of watering) causes progressive differential settlement.

The "Active Zone" Depth

In Gilbert, 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 85233.

"Homeowners in Gilbert often pay for 'Standard Press Piles' that sit inside the active zone. When the Contine clay loam moves, the pier moves with it."
- Elias Thorne, Lead Forensic Engineer

3 Signs of Contine 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

MethodSuitability for Contine clay loamVerdict
Pressed Concrete PilingOften 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 PiersDrilled concrete; excellent stability but higher cost/mess.Viable Option

Apply these Findings to your Home

Request a Free Foundation Inspection for your specific street address.

Licensed TX P.E. Oversight (PE-88XXXX)

Neighborhood Watch

We are monitoring elevated PI readings in these areas:

Central Gilbert

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