Q. There seem to be a lot of products on the market that solve problems with leaky basements. Some are for "dampproofing" and others for "waterproofing." What is the difference?

A.A quick answer is, "their lawyers." For the same reason that a product we used to call a "vapor barrier" is now called a "vapor retarder," many products are now sold for dampproofing rather than for waterproofing.

A product that fills the pores of a material to reduce capillary movement of water through the material can only be called dampproofing. An example is the thin bituminous coating painted on primarily to reduce vapor flow through the wall. These products are useless when bulk water presses against the wall. If the product produces a sealed membrane or forms a continuous film with essentially zero permeability (very difficult), it could be classified as waterproofing. Examples include synthetic rubber membranes and bentonite-based products.