A solar panel module for directly mounting to a roof surface comprises a plurality of solar panels and a low profile, elongated frame including a generally flat, rectangular base having a plurality of substantially planar surfaces for supporting the under surfaces of the solar panels. The panels are removably sealed to the frames at the under surfaces thereof, rendering the upper surfaces fully free and unencumbered for receipt of incident solar radiation. The frame includes, integrally therewith, upstanding walls adjacent opposite edges of the panel supporting surfaces, defining raceway channels for concealed passage of electrical wires connected to the solar panels. The channels and walls have provision for overlapping interlocking with similarly fabricated frames for ease of installation, weather-proofing and high-density panel mounting.