The blank (1) has an elongated shape part comprising two longitudinal edges (2a, 2b). Two end fold lines (3a, 3b) are arranged symmetrical along a mean longitudinal direction of the blank. The end fold lines are located parallel to the directions of the longitudinal edges, where the end fold lines define central portions (6a, 6b) and two end flaps (5a, 5b). Free edges of the two end flaps are located in a bottom of a coffin or around the coffin, and a quilting cover is arranged on an outer face of the blank installed in the coffin.
