Waterproofing across Jersey City, NJ, basement to roof

Much of downtown and the land along the Hudson, plus low blocks toward Communipaw and Newark Bay, sits on old marsh and fill. That ground holds a high water table, so after a long rain the water pushes up and sideways against the basement as hydrostatic pressure, finding the cove joint and every soft mortar joint along the way. Up on the Palisades ridge it is the opposite story. Rock sits close to the surface on the Heights, and water runs along that rock until it reaches a foundation crack, then shows up as a wet stripe on one wall.

Building type matters as much as ground. Downtown rowhouses and brownstones sit on brick or rubble-stone foundations laid in lime mortar, with a front areaway under the stoop and a small drain that clogs with leaves. Frame two- and three-family houses often have a crawl space under the rear addition and leaders that dump right at the wall. Pre-war walk-ups around Journal Square have deep basements with floor drains tied to the sewer. Waterfront towers bring their own list: below-grade garages and elevator pits that sit in groundwater all year long.

Water does not only come from below. Flat roofs behind parapets, rooftop decks built over the membrane on newer condos, and terraces on the towers all leak in ways that look like a basement problem at first, such as a stain two floors down or a damp party wall. We check the roof, the parapet coping and the deck before blaming the foundation, because the cheaper fix is often up top. Our roof deck waterproofing work starts by lifting a few pavers to see the membrane underneath.

Our Jersey City office sits at 218 Newark Avenue, a short walk from the Grove Street PATH station, and the phone is answered 24/7. When water is coming in at two in the morning, you talk to a person who can send an emergency crew the same night when one is free, with pumps, wet vacs and drying equipment on the truck. For slower leaks we set a visit, trace the source with moisture meters and a look at the outside drainage, and walk you through what we found before anything gets opened up.

Attached buildings take planning. Many rowhouse basements are reached only through a narrow interior stair or a front areaway, and a shared party wall means the water you see may start next door. We bring compact excavation tools, run hoses and pump lines through the areaway rather than the living space, and protect floors on the way down. On blocks with permit or alternate-side parking we plan where the truck stages, keep sidewalks clear and protected, and haul spoil out in bags so the street is left the way we found it.