Modular structural units, not of metal, for the construction of prefabricated buildings; Modular prefabricated building units of non-metallic materials for the construction of buildings; Non-metallic modular units for constructing prefabricated buildings; Modular portable building units of non-metallic materials for construction into relocatable buildings; Non-metallic modular units for constructing relocatable buildings; Non-metallic building materials having waterproofing properties; Non-metallic building materials having thermal insulation properties; Non-metallic panels for interior cladding on buildings; Non-metallic panels for outer cladding on buildings; Non-metallic preformed building panels; Modular wall panelling of non-metallic materials; Mouldings of non-metallic materials for panelling buildings; Non-metallic cladding panels for walls; Non-metallic cladding panels for roofs; Non-metallic fireproof panels for use in building; Non-metallic interlocking panels for building