I saw a crew one time dig a trench on one side of an old building that has a stone foundation. Rain and snow melt were penetrating the foundation, which slopes downward from the source of the water in this area. Now I'm about ready to close on a small row house that has the same problem. It's a buy/fix/flip. I have the same issues in front. Does anyone know what the proper procedure is for ceiling off the water from the outside? What sort of membrane to use, etc.? Thanks.