Abstract: A sealed lay-in wireway comprised of channel members secured together in end-to-end relation with sealing flange gaskets thereinbetween and having longitudinally spaced covers having resilient gaskets extending continuously along their periphery and having a pivotally mounted bridging member extending along their open sides between the adjacent ends of their covers which shiftably mounts a sealing plate thereunder, the sealing plate having gasket material at each of its ends which bears against inwardly extending flanges of the channel members when drawn upwardly by a camming mechanism carried by the bridging member, the upper surface of the sealing plate at the same time bearing against gasket material carried by the ends of the covers to cooperatively perfect a seal at all of the joints.