To make a long story short I was contacted by an organization that owns a house and is ready to cut their losses on a house they own. The problem is that there is a major water leak and every time it rains or the lawn sprinklers run so does the water into the house. This house is a split level home, they started with a slab foundation, on the south and east sides there is a retaining wall poured on the outer edge of the slab to hold the dirt off of the wood framed walls. At this point I am guessing the water is entering between the seam of the retaining wall and slab. Either there is existing tar that has cracked, no tar, or the wall has had a structural failure and has a major break in it. The only way to find out is to excavate it. Upon excavation and discovering what the exact problem is will determine what needs to be done for repairs. IF there is no structural damage my plan will be to pressure wash the wall till clean, allow it to dry for several days, put one coat of hot tar on the slab/retaining wall joint area, let that dry then come back in and apply a butyl tape over the applied tar and finally apply one coat of tar over the entire wall. Any one got a better suggestion on application or materials?