19 building materials; namely, lumber, plywood, woodbeams, wallboards, wood and/or vinyl siding, cement mix, plaster, spackling compound; prefabricated structures; namely, garages, homes, cottages, decks, screened-in porches, prefabricated wood trusses, gable ends, arch ribs; floor coverings; namely, wood tile and materials used in connection therewith, sold as a unit