Packing containers and blanks therefor

A packing container of the ridge roof type of the kind which is adapted to be opened by folding out again a bellows fold (B) formed at the top closure of the container in order to form an emptying opening (16) in the shape of a pouring spout. With the object of making the container liquid-tight and at the same time easy to open perforation (15) is arranged aove the said bellows fold (B) below which the sealing fin (10) delaminates when the container is opened. The seal between the material layers forming the sealing fin (10) below this perforarion is considerably weaker or almost negligible compared with the seal between material layers above the tearing perforation.