Abstract: A self-cleaning grain bin roof configured to allow ventilation through the roof ribs which has a trapezoidal shaped inner rib with ventilation orifices therein and a spaced apart and partially covering outer rib configured to inhibit precipitation from falling through the orifices while permitting air to be blown from inside the grain bin outside. The trapezoidal shape providing for a self-cleaning ability in that if matter is blown to the orifices by positive pressure in the grain bin, it will, in the event of a loss of pressure, either fall outside of the orifices and slide down one of the slanted trapezoidal sides, or return to the grain bin. If debris blown by wind gathers on the roof, it will be blown out from under the outer rib by the airflow through the orifices.