19
Building materials (non-metallic); Windows, not of metal; Other than goods for protecting against fire, including fireproof membranes, boards, grout, doors, partition walls, casings, telephone valves, ceilings, cladding, bathroom plaster, fireproof building materials combined with boards and grout
20
Window fittings, not of metal
37
Building construction; Other than cleaning of buildings, apparatus and machines, in particular removal of asbestos and other harmful substances, cleaning of textiles, renovation after damage caused by fire and water, maintenance of industrial apparatus and equipment, including escalators and lifts, installation of fireproofing systems, maintenance of air-conditioning and ventilating systems, repair and maintenance of electrotechnical goods and mechanical engineering goods, demolition, hydraulics, repair of structures, dehumidification of buildings, renovation after damage caused by fire, smoke, fire-fighting water, water from pipes and floodwater