The present disclosure includes a system and article of manufacture for a door assembly for rolling and unrolling, or retracting and extending, a door curtain. The door assembly may include various mechanisms to protect a door curtain from wear and abrasion, as well as muffle noise associated with the operation of the door curtain. The door assembly may comprise a curtain shaft. A door curtain may roll and/or unroll (e.g., open and/or close) on the curtain shaft. The door assembly may further include an insulator shaft, which may receive or hold a door curtain insulator or insulators. A door curtain insulator may attach to the insulator shaft as well as the curtain shaft and/or door curtain itself. In operation, as the door curtain is rolled up, one or more lengths of insulator may be unrolled from the insulator shaft and layered, or interleaved, between consecutive layers of rolled up door curtain. Similarly, as the door curtain is unrolled, one or more lengths of insulator may be rolled up or wound about the insulator shaft, such that no insulator travels with the curtain as it unrolls towards a closed position. The door assembly may also include a mechanism for compensating for a difference between an angular speed of a door curtain on a curtain shaft and an angular speed of a door curtain insulator on an insulator shaft.