non-metallic building materials, namely, asphalted felts, wood beams, concrete beams, bihiminous roof coatings, concrete bricks, fireplace bricks, cement mixes, cement posts, ceramic tiles, non-metallic chimneys, concrete, non-metallic door units, fences, floor tiles, girders, glass panes, granite, gravel, grout, lumber, wall panels, paving, playwood, refractory blocks, roof coatings, roofing felts, roofing slates, sand, sealants for roofing, shingles, siding, ceramic tiles, wall boards, window frames, wood beams; non metallic unbending pipes, namely, gutter pipes, water supply pipes, waste liquid discharge pipes, gas pipes, drain pipes; asphalt pitch and bitumen; non metallic portable buildings, marble, natural and artificial stone