Closure for roof drain

The combination of a roof, roof drain and closure device, said roof drain being defined by an opening in said roof for draining water therefrom, a closure device including an inverted generally cup-shaped cap, said cap having an apex portion and a peripheral skirt, said peripheral skirt having a lowermost peripheral edge portion terminating in a peripheral terminal edge, peripheral sealing means carried by said peripheral terminal edge for sealingly engaging a peripheral area of said roof outboard of said roof drain in closed position of said closure device, said peripheral skirt being devoid of aperture means from said peripheral terminal edge to a predetermined height thereabove, aperture means above said peripheral edge portion beginning at said predetermined height whereby in said closed position water will accumulate upon said roof to a height generally equal to said predetermined height, rod means connected to said apex portion, and means for connecting said rod means to said roof drain whereby upon axial motion of said rod means said peripheral sealing means will be brought into and out of contact with said perhperal area to respectively form and break a seal between the latter and said peripheral sealing means.