The tiles are slid into the cast iron frame, held in position by pieces of cardboard and then plastered over from the back with bonding plaster. Once dry the fireplace itself can be fitted. Once set into the fireplace the tile set cannot easily be changed without removing the fireplace from the wall.
Tile sliders were introduced into cast iron fireplaces at side of the opening from 1860-1880. They allowed 6 inches tiles to be slid down at either side of the fireplace opening. There is no practical reason for the tiles, they are purely decorative.
With hand painted tiles the artist painted directly onto a plain tile. Art Nouveau tiles used a process of tube lining where slip was trailed onto the surface of the tile. This formed raised lines separating the areas where different colour was wanted. Coloured glazes were poured into the areas of the tile formed by the tube-lined decoration.