Durability is never a designer's only concern in a project; it's always balanced with aesthetic requirements, budgetary constraints, and other needs. Still, for most building owners it has a high priority. Because water causes most building problems, reducing masonry's water permeance increases its durability. The checklist can help designers select appropriate materials to achieve the goal of durable clay brick and concrete masonry. The recommendations apply to exterior walls above grade. Many of the recommendations are keyed to maps showing the weathering index for different regions of the United States.