CASE STUDYBonita Beach Foundation Stabilization

Location: Bonita Beach, Bonita Springs, Florida – Coastal Residential Area
Project Type: Foundation Underpinning & Stabilization
Client: Private Beachfront Homeowner
Completion Date: March 2023

Analysis

The west coast of Florida, particularly the Bonita Beach area of Bonita Springs, suffered extensive structural damage after Hurricane Ian in 2022. Coastal properties experienced significant foundation challenges due to soil washout, erosion, and rising groundwater levels caused by storm surge and flooding.

This beachfront home on Bonita Beach, situated close to the Gulf of Mexico and adjacent canal systems, required an underpinning solution to restore foundation stability and prevent further movement. Coastal Foundation Solutions was contacted to design and implement a customized underpinning strategy that would address the unique soil and groundwater conditions characteristic of Bonita Springs’ coastal geology.

The site posed several challenges common to the Southwest Florida coastal environment: high water tables, fluctuating soil moisture, and limestone bedrock layers. Our team utilized prior subsurface data and extensive local knowledge to prepare a plan that could withstand future environmental pressures.

Solution

Recognizing the need for robust support in a challenging coastal environment, the Coastal Foundation Solutions team selected Helical Micro Pulldown Piles for this project. The team began with a static load test in March 2023 on a test piling to confirm design parameters:

• The test pile achieved a compression capacity of 32 tons while extending to a depth of 34 feet.
• The pile torque recorded at 4,800 ft/lbs translated to approximately 24 tons in compression.
• A 5-inch grout column was installed, adding roughly 8 tons of compressive strength, resulting in an overall capacity near 0.592 KIPS.

This thorough testing assured the team of the method’s reliability under Bonita Beach’s coastal soil conditions.

With this data, the team proceeded with a comprehensive installation of underpinning piles around the home’s perimeter and interior. A total of 28 underpinning piles were installed around the exterior, while 20 piles reinforced the interior foundation.

During the installation of exterior piles, the team encountered significant groundwater infiltration beneath the existing foundation footers, a frequent issue in this region due to proximity to the Gulf of Mexico and canal systems surrounding Bonita Springs. This required 22 hours of dedicated excavation and dewatering to maintain site safety and structural integrity.

The existing perimeter grade beams, found approximately 30-36 inches below grade, were evaluated by uncovering and inspecting the reinforced concrete beams (measuring approximately 30 inches wide by 12 inches deep with four #6 reinforcing bars). This confirmed the need for new foundation piles rather than underpinning piles on the perimeter grade beam to optimize structural support.

Several piles encountered “refusal” or “spin-out” during installation when meeting dense limestone bedrock typical of the Southwest Florida coastal geology. Refusal happens when soil resistance exceeds the downward force of the pile’s helix plates and the excavator’s thrust. To compensate, extensions and additional piling were installed to maintain load requirements, following the guidelines set by the Engineer of Record.

Results

Despite the site’s complexity—including groundwater challenges, limestone bedrock refusal, and structural grade beam interference—the Coastal Foundation Solutions team successfully completed the project on schedule and with minimal disruption to the homeowner.

• 28 exterior underpinning piles were installed, including 12 piles that encountered refusal and required 16-inch helix extensions.
• 20 interior underpinning piles reinforced the home’s core foundation, significantly enhancing its load-bearing capacity.
• All piles were installed with galvanized steel components suitable for the saltwater marine environment of Bonita Beach, Bonita Springs.

This project significantly improved the home’s structural stability, protecting it against future storm damage, erosion, and soil movement common in Florida’s coastal regions. The comprehensive dewatering and excavation efforts ensured a safe, dry worksite, preventing additional soil instability around the foundation.

Products Used

• SS150 8” x 10” x 12” 76″ Helical Piles
• 16” Helix Extensions for piles encountering refusal
• Galvanized Steel Components for corrosion resistance

About the Author

Charlie Garcia is a Florida-certified building contractor and marine construction expert with over 25 years of experience serving coastal communities throughout Southwest Florida, including Bonita Springs, Naples, and Cape Coral. Based in Cape Coral, Charlie holds multiple licenses, including Florida License #CBC1252534 and #CBC1263386, as well as certifications as a:

• Certified Helical Piling Inspector
• Certified Deep Foundation Contractor
• Certified Foam Injection Contractor

Charlie is a trusted authority on seawall repair, erosion control, foundation stabilization, and marine structural restoration—bringing technical precision and environmental stewardship to every project in Florida’s coastal environment.