Insulating structure

The insulating structure comprises a plurality of corrugated sheet metal layers (10) which are superimposed on and fixed firmly to each other. Each corrugated sheet metal layer (10) is produced from aluminium and has a series of rectilinear ridges (12) and depressions (14) which are parallel with each other. The orientation of ridges (12) and depressions (14) of a layer (10) is arranged at an angle relative to the orientation of ridges (12) and depressions (14) of the immediately adjacent layer(s) (10). All of the corrugated sheet metal layers (10) preferably have openings (16).