A deck for the roof of a grain bin includes a plurality of deck units each having a plate having an upper face and a lower face and openings spaced from each other and adjacent each longitudinal edge of the plate. The spacing of some of the openings is substantially the same as the spacing of openings in the roof whereby the plate may be attached to the roof. A pair of ring segments extend substantially perpendicular to the elongate plate and rest upon the plate. Openings are in the ring segments and at least one of which is aligned with openings in the plate whereby the ring segments may be attached to the upper face of the plate. A riser extends upwardly from the ring segments opposite the plate, and the riser and ring segments are attached. A deck plate is attached to the riser opposite the ring segments.