Abstract: A door assembly for a kiln that includes a door frame formed by prefabricated vertical frame members that are interconnected with prefabricated lateral frame members. Insulated panel sections are replaceably supported by the door frame. Replaceable, peripheral door seals are held in track ways. The track ways are defined by the vertical and lateral frame members. Each lateral and vertical frame member includes a plurality of T-slots for receiving threaded members that are engagable with threaded fasteners used to hold the panel sections to the door frame. The door assembly includes clamp pressure receiving structure for receiving a clamping pressure exerted by a clamp mechanism forming part of the kiln structure whereby a sealing engagement is provided between a peripheral seal on the door frame. A roller extending outwardly from the door assembly is engagable by another, passing door assembly.