Roof damage from hail force is typically the result of improper application or inadequately manufactured materials.
Every year building owners file a large number of property loss claims resulting from hail damage to a roof system. In fact, the percentage of roof damage from hail is so large that it has spawned a cottage industry of contractors and consultants who chase these types of storms throughout the country in search of roof work. Roof damage from hail force is typically the result of improper application or inadequately manufactured materials.
Small hailstones should not damage the membrane. However, it has happened. The best way to determine the size of the hail is by inspecting the metal components of rooftop equipment or copings. Indentations from hail over the metal coverings can be measured to determine the actual hail size. It is also a good idea to investigate adjoining roof areas or surrounding buildings to determine if the same storm produced similar damage.