An improved horizontal support member for a demountable wall system which decreases the number of pieces which must be cut and folded, and subsequently assembled, to form a frame to which the gypsum board panels of the wall are assembled while increasing the strength and stability of the wall. The support member is formed from an elongate sheet of metal by making a series of longitudinal cuts in the metal and then folding the cut metal edges along lines which are substantially parallel to the longitudinal cuts to form first and second bars. The space between longitudinal cuts acts as a spacer to maintain the first and second bars in spaced, substantially parallel relationship.