To add to this, inadequate waterproofing maintenance causes three major problems: 1) Saltwater corrodes rebar and i-beams, making them vulnerable to catastrophic failure. 2) Water displaces sand and doesn't really compress. This causes it to wash out the sand under the building...until the water leaves and all you have is a void. 3) Voids, aka sinkholes, lead to catastrophic collapses because the building doesn't settle gradually...it goes from "everything is fine" to pancaking into the "new basement".