Metallic building materials; ventilation ducts and ventilation fittings of metal or substantially of metal, with and without seals, dampers, connectors and metallic suspension means for said goods; screws, nails, rivets, metal fittings and strips for building purposes; gutters and downpipes as well as jointing means and means of attachment therefor; metal ladders, metallic protective cages for ladders, metal railings; metallic means of attachment for ladders and railings, metallic roof bridges, metallic roof security means in the form of ladders, roof bridges and railings and means of attachment therefor