A composite layered sheet, comprising at least a) a fire-protection layer A with an intumescent composition based on an alkali metal silicate and, applied on the two sides, b) protective layers B and B', and c) a substrate layer C composed of wood, fiberboard, gypsum plasterboard, or calcium silicate board, paper, metal, plastic, or of another fire-protection layer, and production process, and use as core material for a fire-protection door.