Abstract: A wall system for the construction of buildings comprises an inner sheet steel facing panel having a base and two side walls extending along opposite substantially parallel side edges of the base and defining a recess with the base. A sheet of thermal and acoustic insulation material is located in the recess of the inner panel. An outer sheet steel facing panel having corrugations running in a direction substantially perpendicular to the side edges of the base is secured to the inner panel by fixing to flanges at the ends of the side walls of the inner panel.