This cover channel (41) is configured for covering, at least in part, an edge (29) of an insulating panel (4A) with two outer walls (21, 23), the cover channel comprising an elongated body (43) comprising a cover portion (45), two outer portions (51), protruding respectively from an edge of said cover portion in a substantially perpendicular direction relative to the cover portion, and two clamping portions (53), each protruding from the cover portion alongside one of the outer portions for clamping a rim portion (31, 33) of one of the two outer walls. According to the invention, the cover channel (41) comprises a sealing gasket (63) provided along the elongated body (43), resting against the cover portion (45) within at least one of the clamping gaps (55).