Tile making (roofing tiles)

The making of clay tiles by hand or in small batches for roofing. See the separate entry for tile making (flooring and wall tiles).

Once the clay has been extracted from the ground, unwanted matter is removed and it is mixed to the right consistency for tile making. The clay is then shaped in a mould, and sand used to prevent the clay from sticking it. When moulding a tile, it is vital that no air is trapped inside the clay. Excess clay is removed by running over the mould with a wire. The tile is dried until it is ‘white hard’ and then fired.

In some cases, tiles were made in a mould with a pattern carved in relief to indent a pattern on the clay slab. The slab would be dried and the impression filed with white pipe clay. After further drying this would be shaved flat. A glaze of lead ore was sprinkled onto the surface and the tiles were then fired.

Encaustic tiles are made by mixing two types of clay: plain clay and liquid clay. The plain clay must be left with an impression which is then filled in with the liquid clay of a different colour, these are then fired together. These tiles were made from the twelfth to sixteenth centuries. This skill disappeared with the dissolution of the monasteries but was brought back to life in the nineteenth century by Herbert Minton’s development of dust-pressing.

The colour of the tile is determined by the chemical composition of the clay, the fuel used to fire the tile, and the levels of oxygen available during the firing process. Iron oxide give the brick a red colour, very high levels of iron oxide give a blue colour, limestone and chalk added to iron gives a buff/yellow colour, magnesium oxide gives a yellow colour, and no iron or other oxides gives a white colour.

• Market issues: handmade tiles cost more than mass manufactured tiles
• Market issues: The market is fairly buoyant at the moment but the future will depend on a continuing trend for architects and individual house owners to want something different from what is available ‘off the shelf’. The handmade tile trade is not affected by the general fluctuation of housebuilding, as it is a limited niche market. 70% goes to restoration projects and 30% to new builds. A present increase in the demand for small runs of tiles is from new designs by architects or tweakings of standard types of tile. Exports in particular to America, Holland and China.
• Market issues: Different regions have different traditional tiles which depend on the local clay – conservation officers don’t always understand what they’re doing and use foreign tiles rather than specifying the local tile
• Organisation: Although a few tiles are made by hand as a cottage industry, the majority are produced within larger firms who make large numbers of machine made tiles as well. Within this set-up, some tiles are bespoke, while the majority of handmade tiles are simply premium items at the top end of a company’s range and come in standard shapes and colours.
• Supply of raw materials: Clay all comes from the UK. Original works were sited near clay deposits, so very little transport costs involved for the raw material. Finished tiles are very specifically connected to the clay source – different regions have different traditional tiles which depend on the local clay. Some clay streams are at risk of disappearing.
• Supply of other materials: Certain types of tile are coal-fired to achieve the right finish and there are currently issues in the supply of coal
• Training issues: There are no specific courses, but there would be no point. Training has to be done by physically making the tiles. The basic skills are fairly easy to teach and learn, although it can take many years to master the techniques.