Abstract: A heating wall construction for horizontal chamber coke ovens comprises spaced apart stretcher stone walls with header walls extending therebetween and being spaced from each other to define vertical heating flues therebetween. The header walls are hollow or have a hollow portion which defines a vertical heating flue for their fuel supply and they have transfer slots in the walls which connect at various levels for transferring the heating gases from the hollow central portion to the flues. The runner stones of the heating walls have a thickness of less than 110 mm and the hollow headers are over 200 mm wide at their widest point in the central region of the heating flue and they are much wider than 100 mm at their abutting or tie in point in the stretcher stone walls.