prefabricated building materials, primarily of metal, namely, glass porch enclosures with frames of metal

PORCH ENCLOSURE ASSEMBLIES COMPRISED OF WINDOW FRAMES HAVING SCREENS ACROSS THE FRON THEREOF AND TRACKS BUILT THEREIN WITH A PLURALITY OF SASHES SLIDABLE RELATIVE TO EACH OTHER AND TO THE TRACKS AND MOUNTED WITHIN THE TRACKS, THE SASHES EACH CARRYING A GLASS PANEL THEREIN