| 摘要 |
When a snowfall occurs, it builds up a layer (5) on the over roof (3), i.e. at a distance from the outer surface of the external roof (1). Melted water can pass freely through the over roof on to the external roof (1) and drain away to the guttering (2). - The snow (5) cannot absorb melted water by capillary action in the seam way as would occur were the roof not to be present, which results in the prevention of ice formation on the external roof (1). |
