A gas turbine engine combustion chamber arrangement includes an annular outer wall and annular inner wall including an upstream and a downstream row of tiles. The downstream end of each tile in the upstream row of tiles has a rail extending towards and sealing with the outer wall and a lip extending in a downstream direction towards the tiles in the downstream row of tiles. The outer wall has a row of apertures to direct coolant onto the lips of the tiles in the upstream row of tiles. The downstream end of each tile in the upstream row of tiles has a plurality of fences extending in a downstream direction from the rail and each fence extends from the outer surface of the lip towards the outer wall. The row of apertures in the annular outer wall is arranged to direct coolant onto the lip between two circumferentially adjacent fences.