adjacent kiln car bases and also between each base and the wall of the kiln to prevent or reduce damage and abrasion of the bats 18 it is not necessary to form an airtight seal around the base of the kiln car because any heating of the trolley 10 is likely to be due almost exclusively to penetration of radiant heat from the flue 13 since conduction and convection effects are minimal for the reasons referred to above the embodiment of the invention described above provides a kiln car base which has a very low thermal mass compared with the conventional solid fire brick base which improves heat insulation between the flue and the metal trolley owing to the superior thermal insulating properties of the lightweight insulating materials used and which additionally has means for forming the heat seal with the walls of the kiln and with adjacent kiln car bases the base is capable of carrying the usual load due to the weight of the superstructure and ware however it is not a particularly skilled operation to assemble the base the components are relatively small and lightweight and only a few different types of component are required so that the whole assembly operation can be carried out very readily additionally the components for forming a base can be packed for freighting purposes into a relatively small volume and weigh less than the conventional fire bricks used for a conventional base the low thermal mass insulating material can be.