A solar panel roof surface effectively uses solar panels supported by an open roof support substructure having a series of parallel hollow support beams. These hollow beams support the solar panels on a top surface and accommodate drainage along the beams. The solar panels are secured to an upper surface of the hollow support beams and in combination therewith define a closed sloped roof surface. The series of solar panels are positioned on the beams to define elongate segments of abutting panels. The abutting panels include a sealing arrangement between panels to allow flow of water along the length of the elongate segments. The hollow support beams include a top surface with a central securing slot positioned between panel segments and panel segment support surfaces either side of said securing slot for supporting edges of the solar panels. Fasteners engage the securing slot and the upper edge of the panels to secure the panels to the upper surface of the support beams.