Abstract: A prefabricated roofing panel has two opposite parallel edges bevelled at an angle to the top and bottom flat surfaces, and a portion of each bevelled edge is blunt cut adjacent one of the flat surfaces to enable interlocking of the panels. Each panel has a sidelap on one side extending across a bevelled edge, and a headlap at one end. The panels are installed with adjacent bevelled edges in interlocking engagement.

Abstract: A hollow tubular roofing cant has a plurality of perforations for permitting ingress of moisture or gases from the roofing system and a plurality of one-way vents for permitting egress of moisture or gases into the atmosphere. The tubular roofing cant may be of triangular or trapezoidal cross-section.

Abstract: A roofing system comprises a plurality of prefabricated panels and spacers. The panels comprise a base member and a lamina covering. The lamina extends from one end of the panel to provide an overlap with an adjacent panel and is spaced inwardly of side edges of the base to form exposed parts. In accordance with the method, a row of prefabricated panels is secured to a roof, and a row of spacers is then applied adjacent the row of panels. A second row of panels is then placed adjacent the row of spacers, and a closure is placed over the spacers and onto a portion of the two rows of panels. The panels, lamina and closure are of readily available, standard sized materials.