The installation depth for helical piers is not a fixed number; instead, it is determined by the specific subsurface profile and the need to reach stable, load-bearing strata. According to the provided guide, depth requirements can vary significantly based on soil type:
- Soft Clay: Approximately 5–15 feet.
- Silty Clay or Clay Loam: Approximately 8–20 feet.
- Loose to Dense Sand: Approximately 10–25 feet.
- Gravel or Sandy Gravel: Approximately 12–30 feet.
### Determining the Correct Depth To ensure the pier has reached competent soil, contractors use two primary methods:
- Geotechnical Investigation: Soil borings and test pits identify the depth of the load-bearing strata before installation begins.
- Real-Time Torque Monitoring: As the pier is screwed into the ground, a hydraulic torque motor measures resistance. This torque reading is correlated to soil capacity using ICC-ES AC358 formulas. The installation continues—often using extensions—until the required torque and design depth are achieved.
At a minimum, piers are typically installed beyond the frost line to prevent movement caused by freeze-thaw cycles.
Related FAQs
-
Can Polyurethane Foam Stabilize a Settling Home without Underpinning?
Read More »: Can Polyurethane Foam Stabilize a Settling Home without Underpinning?Polyurethane foam is generally not recommended for structural foundation stabilization. While it is an effective tool for slab jacking—which involves lifting non-structural concrete like sidewalks, driveways, or interior slabs with less than 2 inches of settlement—it lacks the capacity to…
-
Is Polyurethane Foam Injection a Permanent Solution for Foundation Lifting?
Read More »: Is Polyurethane Foam Injection a Permanent Solution for Foundation Lifting?Polyurethane foam injection is not a permanent solution for structural loads or foundation settlement. While it is an effective tool for non-structural applications, such as filling minor voids or leveling interior slabs, sidewalks, and driveways, it lacks the engineered capacity…
-
Which is Better for Fixing Uneven Concrete Slabs: Foam or Piers?
Read More »: Which is Better for Fixing Uneven Concrete Slabs: Foam or Piers?The choice between polyurethane foam and steel piers depends on whether you are looking for a surface-level lift or a permanent structural solution. While both address settlement, they serve very different purposes: When to choose steel piers: We recommend engineered…
-
Why do some Foundation Experts Recommend Steel Piers over Polyurethane Foam for Structural Issues?
Read More »: Why do some Foundation Experts Recommend Steel Piers over Polyurethane Foam for Structural Issues?We recommend steel piers over polyurethane foam when a permanent, engineered structural solution is required. While polyurethane foam is an effective tool for filling voids and performing minor, non-structural lifts for concrete slabs (typically under 2 inches), it is not…
-
What are the Pros and Cons of Polyurethane Foam Vs. Steel Piering?
Read More »: What are the Pros and Cons of Polyurethane Foam Vs. Steel Piering?When evaluating polyurethane foam vs steel piers, the choice depends on whether you need a temporary surface fix or a permanent structural repair. Polyurethane Foam Injection (Slab Jacking) Steel Piers (Helical or Push Piers) While foam is a suitable tool…