A joint assembly (10) for a pipe (12) and a backing mechanism (18) therefor. The joint assembly (10) provides for sealing a pipe (12), the pipe (12) having an elongate axis (21), an inside surface, an outside surface (26) and a flange (42) disposed at one end thereof, the flange( 42) having a front surface (46) facing away from the pipe (12), a back surface (48) and an inner periphery (50) defining an outlet of the pipe (12). Sealing material (16) is disposed adjacent the front surface (46) and the inner periphery (50) of the flange (42). A backing member (58) is adapted to engage the flange (42) and to apply a compressive load from the back surface (48) of the flange (42) toward the sealing material (16) adjacent the front surface (46) and the inner periphery (50) of the flange (42) so as to seat the sealing material (16) along the inner periphery (50). Seating is against a surface of a cooperating joint member (14) adjacent the front surface (46) of the flange (42).