Abstract: A rotary hearth for a kiln assembly in which the refractory material-bearing portion of the hearth is supported by a metal frame from below and is contained peripherally by a refractory buttress secured to the frame. In the preferred form of the invention, the refractory buttress comprises a lower layer of slightly circumferentially spaced buttress block and an upper layer of refractory rim tiles interlocking with the buttress blocks. The hearth is free of metal structural components in regions of high heat and thus free from the problems of cracking and jamming associated with assemblies of the prior art.