I am designing a house addition in orange county, upstate new york. there is a high watertable that exists, and a nearby pond. The existing house has a partial basement that does require a sump pump. The owners are hoping that we might be able to find a "water tight" solution for the new basement, so that they can finish it without moisture being a problem.
Is there a "Seamless, or welded seam" material that might act as a impermiable skin available?