Abstract: A preformed roof cover element consisting essentially of a quadrilateral panel (1) with the shape of an isosceles trapezium whereof the two non-parallel sides (2 and 3) have rims (4 and 5) extending substantially over the whole length of the sides. The rims (4 and 5) are raised on the same panel (1) side. The length of one of the trapezium bases (6) is substantially equal to that of the other base (7) increased by twice the thickness of the rim (4 and 5) wall so as to enable the rim (4 and 5) ends (8) to be engaged on the shortest base (7) side with the panel part bordered by the ends with a predetermined element between the ends (9) located at the longest base (6) side of another element extending in a projection of the predetermined element and parallel to the rims (4 and 5).

Abstract: Process for continuously galvanizing steel sheet by passing the sheet through a bath consisting of zinc, aluminium and silicon, the aluminium content ranging from 0.05% to 0.5% by weight and the silicon content from 0.005% by weight up to saturation.There is neither formation of aluminiferous floating dross nor formation of bottom dross in such a bath.