Not always.

According to the art of construction, vapor barrier film should be installed in all rooms.

However, it should be borne in mind that there is no moisture in most rooms, and Crossin Attic Soft foam, for example, has a very low soak factor.

Taking into account the above factors, you can dispense with the vapor barrier film, but be sure to use it in rooms that are particularly exposed to moisture, including bathrooms, kitchens, laundry rooms and drying rooms.