A cover plate, to cover part of a space between a door and a door surround, comprising at least one pressure element secured to at least part of the external face of the cover plate. The pressure element comprises two sheets, an external sheet and an internal sheet, these two sheets being superposed and fixed together. The internal and external sheets are respectively made from materials that have different thermal expansion properties causing at least a contraction of the internal sheet with respect to the external sheet, at least for a range of temperatures comprised between −20° C. and −50° C.