A combustion chamber is disclosed for a turbojet engine in which the combustion chamber has a forward intake, a rear exit and a perforated casing extending between the intake and exit. The combustion chamber also has at least two rows of insulating tiles arrayed on the casing in forward and rear rows with both rows extending circumferentially around the inner surface of the casing bounding the combustion chamber. Each rear tile has a forward edge portion with a sloping wall and each forward tile has a tapered rear edge portion overlapping the forward edge portion with a clearance therebetween such that the tampered rear edge portion and the sloping wall bound a slot opening into the combustion chamber and slanting towards the rear of the combustion chamber to facilitate the formation of an air cooling film on inner surfaces of the tiles. The cooling air passes through the perforated casing, into the space between the casing and the tiles, through the clearance between the tiles and through the slot into the combustion chamber.