An insulated structural cabinet for an appliance includes outer walls that are attached together to define a structural envelope that is operable from an expanded state that includes an expanded interior volume of the interior cavity, to a final state that includes a contracted interior volume of the interior cavity, wherein the contracted interior volume is less than the expanded interior volume. An insulating material disposed throughout the interior cavity in the expanded state. Operation of the structural envelope to the final state densifies the insulating material. Operation of the structural envelope to the final state is performed by a vacuum pump that expresses air from the interior cavity. The structural envelope is also operable from a performed state to the expanded state via an expanding device, and subsequently operable from the expanded state to the final state.