The invention relates to a method of manufacturing a membrane (1) from a blank (39) by a cure, which membrane comprises two rubber layers (40, 41) and a fabric-formed reinforcement layer (19), positioned between said rubber layers. In order to counteract and prevent respectively undesirable displacements of the reinforcement layer (19) membrane sections, which are movable in an application position, are manufactured according to the invention having a form, which deviates from the application form, and/or are exposed to stretching during the cure in order to within the membrane section bring about a displacement of said reinforcement layer (19) across a portion of at least one of the rubber layers (40, 41) and consequently a position, which deviates from the blank building up during the cure. The invention also relates to a membrane, manufactured according to this method as well as a mold tool designed to carry out the method and the manufacture of the membrane respectively.