Abstract
Long-term evaluation of the sliding performance of coated steel roofing and a technique for maintenance of roofs designed to facilitate on going disposal of snow by sliding are examined. Properties of coated steel roofing change with time due to chemical deterioration caused by ultraviolet rays and mechanical deterioration caused by sliding snow. With polymercoated steel roofing there is a period of about 18 years after initial deterioration during which sliding performance remains constant. Furthermore, changes of sliding performance with time of this type of roofing can be evaluated based on adfreezing strength and coefficient of friction at the interface between the snow and roofing material. Hence, it is effective to evaluate the sliding performance which corresponds to the deterioration curve over time. In addition, it is necessary to plan the maintenance of the sliding function of the roof in consideration of the deterioration curve.
From the above-stated facts, it is necessary to consider the influence of the environmental deterioration factor corresponding to the deterioration mechanism of the material to estimate the service life of the roofing material. A basic concept of the material design technique which can be applied to the sloped roof was clarified by this research.
