Characteristics of galvanized steel U-shaped purlins (Purlin U).

     Z-shaped purlins (c) have one flange wider than the other, which, when flipped over, allows the two sections to fit together snugly, enabling overlapping at the ends above the supports. Z-shaped purlins can be used for single spans or continuous spans, with the ends of each section placed adjacent to each other or overlapping. For long, continuous spans, overlapping at the ends is recommended as it allows the Z-shaped purlin to support greater weight