Abstract: The present noise and heat insulating structural component may form a wall anel or a window element if the component is made of transparent material. Between two substantially parallel outer walls there is arranged at least one auxiliary damping wall forming a plurality of evacuated pockets each having a vaulted or domed surface when the auxiliary wall is substantially free of a load condition. The auxiliary wall may be secured to one or both of the outer walls, for example, by adhesive. Alternatively the auxiliary damping wall may be secured to a further inner wall member or it may be held in position only at its edges substantially intermediate between the outer walls.