A plastic wall board tape having a raised center section and outwardly extending wing areas which have a coating of fibers adhered to both sides. The raised center of the tape is weakened at the top to cause the tape to crease in a straight line when it is folded at an inside or outside corner to define a straight edge at the corner joint. The combination of the rigid water impervious tape and the fibers allows the tape to be applied over imperfectly fitted wall board joints with large imperfections because the fibers will achieve a mechanical bond with the wall board compound or other joint materials, allowing a slow cure, and the tape will not be softened by the compound. When used on an inside corner, the tape can be finished merely by striking the outer edge with compound as the top surface is a finish surface and requires paint only. The tape can have triangular cutouts in the wings and removable end strips to facilitate taping of curved corner joints.