In this paper, we review basic principles of design for two fundamental categories of wall waterproofing systems, barrier walls and cavity walls. We then examine the application of these principles to construction of various types of wall systems, including single-wythe masonry veneers, precast concrete wall panels, glass/metal curtain walls, and exterior insulation and finish systems. For each system, we discuss key features for reliable and durable waterproofing, common problem areas that we have encountered, and remedial options for leaking systems.