Abstract: In an improved refrigerated silo, at least the walls of the structure, and preferably the top in addition, have a monolithic structure including spaced air ducts comprising U-shaped channels held against the interior heat conducting wall of the silo by means of an overlayer of a cured- or foamed-in-place expanded plastic material which adhesively contacts both the channels and the wall of the silo and serves as the principal means of maintaining the integrity of the structure. The ends of the channels are interconnected by suitable manifolds or plenums to provide any desired distribution system through which conditioned air can be passed on either a once-through or a recirculating basis. Because the insulation is foamed-in-place, the necessity for handling large panels of preformed insulation is eliminated, as is the necessity for a frame to hold the insulation in place.