Sink Holes               Symptoms: Sinkholes upland of the wall, visible back-fill mounds in the water near seawall joints (most visible at low tide) Cause: Age, settling, structural failure, insufficient berm at the slab toe of the wall. Slab separation allowing backfill to migrate...

SLAB JOINT (SEAM) SEPARATION Symptoms: Sinkholes, separation in seams, accumulation of rock and sediment at base of affected joint. Cause: Age, uneven exertion of hydrostatic pressure particularly during low tide. Tieback failures. Remedies: Seal seams and cracks, install filter fabric, install supplemental tiebacks (traditional or helical) for additional support...