Abstract: A freezer having its walls constructed of spaced inner and outer stainless steel skins connected together by non-metallic, thermally non-conductive structural members having a configuration which greatly reduces the transfer of temperature extremes and thermal stresses between the skins. The structural members are preferably constructed of glass fibre and possess structural, thermal conduction, and thermal expansion properties which substantially reduce the transfer of heat and thermal stresses between the inner and outer skins as the freezer is subjected to temperature variations between normal processing temperatures of about -50.degree. F. and heat sterilization temperatures up to 170.degree. F. In addition, a novel expansion joint assembly includes a flexible resilient cover strip covering the joint areas of adjacent skins.