Abstract: A panel for roofing or siding applications, with a nailing flange along its rear edge and decorative elements simulating natural materials along its front edge. The panel has a longitudinal locking mechanism that allows the panel to be interlocked with similar panels in front of and/or behind it in a water-resistant latching manner that prevents both front-to-back and upward movement of the interlocked panel, while simultaneously encompassing and protecting the nailing flange. The panel includes a transverse locking mechanism for interlocking the panel with similar panels on either side of it in a water-resistant manner. The panel is preferably made of a blend of rubber tire drums and plastic. The panel has a support structure that offers support against pressure applied to the top of the panel while simultaneously providing an integrated venting system for the system of interlocked panels.