Abstract: A roller assembly for a roller furnace for heat treating slabs is provided with thermal insulation. A metal roller has carrier rings spaced at intervals thereon for carrying a slab to be treated. A needled first fiber mat surrounds the metal roller between the carrier rings and has a fibrous spraying compound sprayed thereon. A binder in the fibrous spraying compound joins the fiber spraying compound with the first fiber mat. A precompressed second fiber mat is laterally disposed between the carrier rings and the fibrous spraying compound. The result is a thermal insulation arrangement which withstands the dynamic stresses of the roller assembly as well as the chemical stresses due to the presence of a hot slab.