Standing seam joins adjacent sheet metal strips above the main roof slope surface. This arrangement helps to organise water runoff. However, it does not automatically guarantee the watertightness of the entire roof. The outcome is also determined by the pitch, flashings and method of fixing. The areas where the continuity of the covering is interrupted require the most attention. The flat sheet metal fields direct water towards the eaves. The longitudinal joint is located higher than their principal surface. This limits direct contact between the flowing water and part of the seam. Effectiveness depends, however, on its construction and the conditions on the roof.