Abstract: A thermal barrier having a corrugated structure which eliminates convection losses and greatly reduces conduction losses. The invention relates to various methods of reducing infra-red radiation loss. The channels formed by the corrugations have a length much greater than their thickness. In one embodiment, grooves are provided in the sheet forming the corrugations. In another embodiment, an infra-red absorptive coating is applied to the sheet forming the corrugations. In the third embodiment, infra-red scattering material is disposed in the channels of the corrugated material.