Abstract: A glass mat reinforced thermoplastic semi-finished sheet material comprising thermoplastic resin and at least two needled continuous and/or chopped glass fibre strand mats is disclosed as well as a method for its manufacturing and its use. Each of said glass mats is needled from the two sides in an asymmetrical way, so that the number of fibre ends protruding from the two major mat surfaces are practically the same, but the length of said fibre ends protruding from the first major surface is substantially longer than the length of the fibre ends protruding from the second opposite major surface. Said glass mats are impregnated with thermoplastic resin, having either their first major surfaces directed towards the outside surface of said thermoplastic sheet, for maximum mouldability, or having their second major surfaces directed towards the outside surface of said thermoplastic sheet, for maximum surface quality of the moulded part.