A door mounting frame structure for a refrigerated cabinet. Each elongated frame member has a longitudinal groove for receipt of a heater wire. A cover plate covers the heater wire groove and provides a surface for contact with a door-mounted gasket. One longitudinal edge of the cover plate is held in place by a longitudinal cover-plate-receiving groove formed in the frame member. The other longitudinal cover plate edge is secured by the covering head of a retainer strip. The strip has a foot portion adapted to be removably inserted in a longitudinal groove formed in the frame member.