This case study examines a concrete panel seawall behind a home in Clearwater, FL, that was experiencing soil loss, creating problematic voids behind the wall.

The homeowner was seeking a permanent solution to stop the erosion—without resorting to the traditional, messy process of excavating behind the seawall to replace the black filter fabric and repack with crushed shell or stone. That method has a high likelihood of failing again and isn’t considered a long-term solution. 

Helicon’s SW-RP1 polyurethane grout injection system offers a clean, efficient, and more permanent permeation solution for seawall soil stabilization. It seals panel cracks, fills voids and defects behind the wall, and, most importantly, stabilizes the soil. The injected polyurethane permeates into the soil, sealing cracks, crevices, and tears in the failed filter fabric—the root cause of the soil loss. For this homeowner, Helicon’s method was a preferred alternative to excavation and fabric replacement. 

Before the project could be completed, Hurricane Milton struck the area, causing a severe washout. The seawall experienced extreme soil loss behind it, creating a massive void. The hurricane amplified the normal erosion process due to a reverse storm surge, which forced water to rush out under extreme hydrostatic pressure. The water followed the path of least resistance, pulling soil with it and escaping through the gaps in the seawall—creating the large voids shown in the project photos. 

With the massive hurricane approaching, our team rushed to stabilize as much of the seawall as possible. Unfortunately, we were only able to complete half of the wall before landfall. The treated section held up exceptionally well—experiencing no soil loss—while the untreated half suffered washouts, though thankfully no structural damage. 

After the storm passed, we returned to complete the remaining section. With both sides now treated, the entire seawall is protected from future erosion, soil washouts, and major storm impacts.

One-part polyurethane grout injection rods were inserted to a depth of one foot below the mudline, spaced approximately 5–6 feet apart at the panel joints of the seawall. From the bottom, about one gallon of SW-RP1 material was injected at 1-foot depth increments, following an upward staging process and stopping one foot from the surface. The grout permeated the soil, sealing voids and panel cracks that caused the original soil loss. 

Following the path of least resistance, the grout forms an impermeable mass—stronger than crystalline bedrock—once cured. This process not only fills voids but stabilizes the surrounding soil, improving the seawall’s structural integrity. A total of 102 gallons of material were used for this stabilization effort. 

Since the entire seawall was sealed, a proper drainage system was necessary. Nine patented JET filters were installed to reduce hydrostatic pressure on the seawall and promote effective drainage. Unlike traditional PVC weep holes, JET filters are designed for maintenance and can be removed and cleaned every six months—reducing the risk of pressure buildup that could lead to failure. 

This project demonstrates how extreme weather can significantly impact soil strength near seawalls—and why Helicon’s one-part polyurethane grouting system is a superior long-term solution. Our method prevents soil loss, treats existing erosion, and provides durable soil stabilization where it matters most.  This short video shows the process.