Abstract: A refractory component which is vacuum-formed from ceramic fibres and which is to be mounted on the external casing or frame structure of a furnace to form part of heat-resisting lining is provided with an internal reinforcement in those parts of the component nearest the casing or frame structure and by which the component is to be mounted on the casing or frame structure. The reinforcement is embedded in the component during formation thereof and is of stiff open mesh form extending in a plane parallel to the general plane of the part of the casing or frame structure on which the component is mounted. The reinforcement is made from heat-resisting metal alloy, refractory clay or recrystallized alumina and is preferably of channel-section or other three dimensional form to increase its stiffness.