How is a Helical Pier Installation Performed on an Existing Residential Foundation?

Installing helical piers on an existing residential foundation involves a precise, torque-driven sequence designed to transfer structural weight to stable soil. The process can be performed from either the exterior or interior of the building, depending on site accessibility.

### Step-by-Step Installation Procedure

1. Site Preparation: The work area is cleared of debris, and underground utilities are marked. For exterior work, a trench is excavated roughly 3 to 4 feet deep to reach the footing base.
2. Pier Positioning: The lead section of the helical pier is positioned at a specific load-transfer point beneath the existing foundation footing.
3. Driving to Depth: Using a hydraulic drive head, the pier is rotated into the ground. Installers monitor torque readings in real-time to ensure the pier reaches competent soil. If additional depth is required, extension sections are added until target torque and depth are achieved.
4. Bracket Attachment: A heavy-duty repair bracket is secured to the pier shaft and attached directly to the existing foundation. This creates the mechanical connection for load transfer.
5. Load Transfer and Backfill: The structural load is shifted from unstable surface soil to the pier. Any voids are filled, and the excavation site is backfilled and compacted.

### Installation Considerations

• Exterior Installation: Offers unrestricted overhead space and allows for full-size hydraulic equipment, though it requires more landscape disruption.
• Interior Installation: Ideal when exterior access is blocked. This requires compact power units and may use low-profile tooling that can operate in areas with as little as 4 feet of headroom.
• Quality Assurance: Installations must comply with ICC-ES AC358 standards. Torque-to-capacity correlations are used to verify that every pier meets the structural design requirements specified by an engineer.