To limit the probability of insufficient positive slope of the roof or construction that serves as a roof after shrinkage and loading of the building, which could lead to inadequate drainage or water pooling, which could lead to:
This is to limit the probability of the premature failure of roofing, which could lead to precipitation or meltwater ingress, which could lead to further deterioration, which could lead to the structural failure of roofs or assemblies protected by roofs, which could lead to harm to persons.