Replacing a facility's roof system is a decision that is quite often put off for a "rainy day".   This is usually the case because a complete roof replacement is disruptive and has a collateral effect on other building systems, equipment and assemblies.  Cost is usually another factor, especially when you consider what the escalating price of crude oil has done to petroleum based building products such as roofing materials.

Most roof systems are warranted by their manufacturers for 10, 15 or 20 year periods.  When properly pitched and maintained, most roofs will have a useful life that reaches and sometimes exceeds their warranty period.  However, even a properly maintained roof may fail due to excessive degradation from ultraviolet radiation (UV) or damage to adjacent systems such as flashings, parapets and copings which allows water to get beneath the roof system.