Tuileries De Beauvais or Beauvais Diamonds are decorative double interlocking clay roof tiles of French origin. The rare roof tiles are often terracotta red in colour but can range from pale red to dark brown and even black in some cases. The tiles are made from terracotta clay, terracotta is not only a term that refers to colour, it also means a ‘sculpture made of earthenware’, which gives an indication as to how these roof tiles were originally fabricated. It is likely that original tiles of this design were moulded by a craftsman by hand, before being cooked on a wood fire where the clay could solidify, forming the roof tile. Today, traditional clay roof tiles such as these have been replaced by mechanical tiles that are molded, compressed and baked.
There are many French clay roof tile designs available, the Beauvais diamond double interlocking tile however is seemingly rare nowadays, consequently seeing a roof decorated with this specific roof tile during a building survey was quite unique. Due to the rarity of these specific clay roof tiles maintenance is likely to be expensive, obtaining Tuileries De Beauvais in a satisfactory condition for maintenance roof repairs may be a difficult task without paying a high price. In terms of when maintenance repairs are to be expected; clay roof tiles often have a relatively long-life expectancy but to give an exact date is near impossible. The factors that affect the life expectancy of this type of tile are as follows, the quality of the original manufacture (of which Beauvais diamonds are regarded as high quality), the firing in the kiln and the make-up of the material within the tile itself.
Whilst inspecting the subject property where the terracotta pan tiles were situated, an investigation of the internal roof space uncovered a quite unique feature of the roof tiles. The main roof space revealed a traditional rafter and purlin construction with no secondary barrier in place, consequently when the lights were turned off a significant amount of daylight could be seen entering the roof space through the raised edge design of each tile (See Image 1). This feature of Beauvais diamonds allows for sufficient ventilation, however there is always a risk of dampness when daylight is visible within the roof space. This dampness can enter the roof space via windblown precipitation, this is a potential design flaw of these specific roof tiles.