19 Pergolas not of metal; non-metallic double glazing panels incorporating insulating glass; non-metallic panels for enclosures for use in the construction of commercial, residential buildings, prefabricated commercial premises, structures, offices, shelters and houses; railings, not of metal, for balconies; ceiling panels, not of metal; ceilings, not of metal; building glass; window glass for building; roofing, not of metal, with integrated photovoltaic cells