Abstract: A laminar jacket for a flexible duct of a heating, ventilation, and/or air conditioning (HVAC) system includes a first film defining an outer surface of the laminar jacket and a second film defining an inner surface of the laminar jacket. The laminar jacket includes a scrim retained between the first film and the second film. Additionally, the laminar jacket includes a longitudinally-extending seam between the first film and the second film that retains the laminar jacket in a tubular shape. The inner surface of the laminar jacket defines a hollow that is configured to receive insulation and that does not have the insulation disposed therein.