| 摘要 |
<p>The metallic roofing elements are made by folding and pressing a long thin piece of metallic sheet into a U-shaped channel, having two upwardly directed edges, one of which carries a lip. When installed the elements are positioned side by side over the roof surface with the lip of the upper element extending down over the upwardly turned edge of the adjacent element. The elements nest into one another for ease of storage and transport. The elements are interconnected by transversely extending members.</p> |
