Tile vaults are a particular type of vault built without centering. Thin bricks (tiles) are placed flatwise, creating a thin surface formed by one or more layers of bricks. The bricks are set with plaster mortar. Plaster mortar hardens very fast, providing a cohesive bond that holds the bricks in place during construction without the need of a centering. The lightness of these vaults, together with the few constructional means that are required, make of this technique a very economic one. Historically, tile vaults have been used in Mediterranean countries, such as Spain, south-east of France, and Italy. At the end of the nineteenth century, Rafael Guastavino (1842-1908) exported this technique to the United States, where he built thousands of vaults. This story is well-known. However, what it is not so well-known is the transmission of tile vaults to the rest of Europe. An ongoing research project about the history of the construction of Belgian vaults has discovered that this technique was introduced in ...