View of a modern recreation of how the roof of the Parthenon was constructed.
The roof was composed of wooden rafters that supported Pentelic marble (!) tiles. Note the lower tiles that are flat, with their edges curved upward. Note too how they were designed so as to be inserted into the supporting wooden rafters—so that they would stay in place.
The joins of these lower tiles were covered with “gabled–shaped” tiles that prevented water from seeping between them. Palmette acroteria were placed at the edge of the roof at the joins of the bottom tiles. In addition, there were decorative lion’s head at each of the corners of the Parthenon.
For a brief description of the Parthenon Click Here.