Property Type: Single‑family waterfront residence with a vinyl/concrete seawall and adjacent patio/sidewalk slab.
Primary Symptoms: Soil loss along the wall line, soft areas and depressions in the yard, and slab edge settlement near the seawall. The owner also reported water migration during tides—classic signs that joints, seams, or hairline cracks were allowing inflow/outflow behind the wall.
Owner Objectives: 1. Eliminate future seawall erosion by sealing leak paths and stabilizing the backfill.
2. Fill voids behind the wall and beneath the slab to restore support.
3. Attempt slab lift within safe structural limits.
4. Keep the waterfront usable during the work and avoid demolition.

Waterfront assets are unforgiving: a leak path that seems minor today can become a conveyor belt for fines tomorrow. Each tide cycle draws water through gaps at panel seams, tie‑back penetrations, or cap cracks, extracting sand/silt and leaving hidden voids. Over time, the lawn sinks, pavers tip, and rigid concrete slabs lose bearing—often first at their edges.

This site presented three intertwined challenges common to coastal Florida:

• Wet‑path erosion: The inflow/outflow of brackish water through cap cracks and panel seams is a powerful force. Any solution had to seal leak paths and stabilize Sealing alone can trap pressure; stabilization alone invites re‑erosion. The plan needed both.
• Uncertain slab lift potential: Slab thickness, reinforcement, age, crack history, and subgrade condition all influence lift behavior. The homeowner’s expectation was set honestly: stability first, then measured lift only if the slab responded predictably.
• Occupied shoreline: Work near water demands containment, small injection shots, and tidal awareness. The team had to protect the waterway, neighboring property, and the owner’s landscaping while executing with precision.

Our program combined two resins and drainage relief to address the problem at its source and its symptoms.

1) One‑Part Polyurethane Seawall Injections (Leak Sealing & Void Fill)

We installed 10 mapped injection points along the seawall line. One‑part polyurethane is a moisture‑reactive resin designed to seek and seal wet paths. In saturated soils, the low‑viscosity resin chases seams and voids and then expands to form a watertight, soil‑binding matrix—locking surrounding sands in place while cutting off the inflow/outflow that had been pumping fines from the yard.

Production: ≈45 gallons (~500 lbs) of one‑part resin in staged lifts, advancing from deeper cavities upward toward cap joints and panel seams. The injection pattern prioritized zones with the most evident seepage and greatest likelihood of backfill loss.

Outcome: Active leaks shut down, voids filled immediately behind the wall, and the backfill mass re‑coupled to the structure.

2) Two‑Part Polyurethane Slab Injections (Stabilization & Measured Lift)

For the adjacent hardscape slab, we used two‑part structural polyurethane. Mixed at the port, the foam expands to fill voids, tighten granular soils, and re‑establish uniform contact under the slab. Our technicians executed metered lift shots in short pulses, monitoring edges and joints to prevent over‑correction.

Production: ≈316 lbs of two‑part foam installed in a targeted grid beneath the settled slab panel(s).

Outcome: Slab re‑supported with incremental elevation recovery in select zones; improved transitions and reduced rocking/trip potential.

3) Hydrostatic Pressure Relief (JET Filters)

To handle the pressure behind the wall after sealing leak paths, we installed 5 JET Filters—engineered weep drains that let water exit while retaining soil. This step helps prevent pressure spikes that can crack caps, open seams, or stress wall panels, especially during king tides and storm surges.

Outcome: A balanced system—sealed where water shouldn’t go, drained where it must, and stabilized so the wall and backfill work together.

Results & Benefits

• Leak‑driven erosion stopped: With leak paths sealed, tide cycles no longer extract fines from the backfill. This is the single biggest step toward long‑term stability on waterfront properties.
• Backfill mass re‑supported: The soil‑resin matrix formed by the one‑part injections closed voids and restored confinement near the wall, giving the structure the passive resistance it needs.
• Slab stabilized with lift where feasible: The two‑part foam re‑established contact beneath the slab and, in target areas, produced measurable elevation gains—improving transitions and reducing trip edges.
• Pressure managed for durability: Five JET Filters now give trapped water a controlled way out—without carrying soil—reducing the chance of new cracks or panel distress.
• Fast, low‑disruption soil stabilization: Small injection ports, rapid cure, and tidy staging preserved the waterfront experience and limited impact on landscaping and hardscape.

Why Polyurethane for Seawalls & Slabs?

• Purpose‑built chemistry: One‑part polyurethane excels in wet conditions, finding and sealing leak paths that cementitious materials can miss. Two‑part foam, conversely, is engineered for slab support and controlled lift.
• Lightweight structural result: Resins add minimal dead load compared to slurry fills, helping avoid added stress on wall panels and slabs.
• Non‑demolition approach: No need to remove concrete, excavate large sections of yard, or shut down the waterfront for extended periods.
• Speed: Rapid cure means many projects finish in a day or two, with areas returning to light service quickly.

Homeowner FAQs

Can you guarantee a full return to original slab elevation?
No. Lift is never guaranteed and depends on slab thickness, reinforcement, historic cracking, and real‑time subgrade response. Our primary promise is stability; we pursue measured lift only within safe limits.

Will the foam harm the waterway?
We deliver in small, controlled shots and use shoreline protection. The resins react primarily within the soil mass. Crews follow coastal best practices to prevent material contact with open water.

How long will this last?
Once cured, polyurethanes are inert and resist moisture. Longevity hinges on drainage, tide exposure, and cap/joint maintenance. The addition of JET Filters helps manage pressure that otherwise re‑opens seams.

Will I see the repairs?
Injection ports are small and patched at completion. Cap crack sealing (if performed) blends with typical seawall maintenance aesthetics.

About Helicon

Helicon is Florida’s trusted partner for seawall repair, soil stabilization, concrete lifting, and foundation repair. We serve homeowners across Manatee and Sarasota counties, delivering clean, minimally disruptive solutions designed for coastal environments.

Seeing wet seams, soft ground, or slab drop along your Bradenton or Sarasota waterfront? Helicon’s polyurethane programs seal leaks, fill voids, and stabilize slabs—often with gentle lift where conditions allow. Call 844‑HELICON to schedule a free inspection and protect your shoreline investment.