After we repair the cracks, a bitumen sealant is applied. Once that dries, we install an Air Gap Water Barrier Membrane using concrete fasteners to the foundation walls, then new perforated pipe (Big O) and ample amounts of clean gravel are installed (creating a drywell) and covered with a geotextile fabric before backfilling. Everything is done at the exterior. The air gap membrane allows for drainage and air flow at the walls exterior. We believe this to be superior then anything else on the market to date.