19 Building timber; building materials, not of metal, namely, ceiling boards, floor boards, doors, windows, timber walls, wooden walls, concrete walls, cement walls, stone walls, glass walls, paper walls, tiles, water and sewer pipes, brackets, braces, beams, eaves, cladding, ventilating and air-conditioning ducts, all of which are not made of metal; building panels, not of metal; buildings, transportable, not of metal; buildings not of metal, namely, residential retail, retirement and commercial buildings in this class, namely, portable non-metal buildings; modular building units not of metal in the nature of inter-locking non-metal components for construction of apartments, homes, offices and buildings; modular units not of metal in the nature of inter-locking non-metal timber panels for constructing relocatable buildings; modular wall paneling not of metal; cladding, not of metal, for building; concrete building elements, namely, walls, slabs, blocks, door and window frames, columns, beams, staircases, pipes, panels, doors, windows, cladding, floors all of which are made of concrete; framework, not of metal for building; modular portable building structures not made of metal