The present invention is concerned with an improved fuel cell stack assembly (10) comprising a metal base plate (20) on which is mounted at least one fuel cell stack (30) and a metal end plate (40), each stack comprising at least one fuel cell stack layer (50) that comprises at least one fuel cell (101, 102) and at least one electrically insulating compression gasket (110), wherein a skirt (130) is attached to the base and end plates enclosing the stack and is under tension therebetween so as to maintain a compressive force through the stack, thereby obviating the need for tie-bars.