It is widely known that most materials used in solar energy conversion and buildingsenergy control applications suffer from two major restrictions, the first being the costseffectiveness of the material in a particular use and the second being durability. In thessolar field, cost has been a very important factor and has restricted development of moresexpensive but efficient materials. The issue of durable lifetime is coupled to the cost;ssince in many cases a more expensive material might have greater durability or operationalslifetime. This investigation looks into selected solar materials and how theysdegrade, fail or cease to function in their specific solar application, and explores methodssby which certain materials can have their operational life extended. This report documentsswork conducted as part of Task 10: Solar Materials RSGD of the IEA Solar Heatingsand Cooling Program.