Counter-intuitively, clay floors are actually very practical. Not only were they very cheap, but they also formed a very hard surface that produced remarkably little dust and so were easy to clean. However, much of clay floor's hardness resulted from what was added to the clay before it was compacted into a floor.  A ca. 1734 builder's dictionary and analysis of surviving Montpelier clay floor show that sand, pieces of brick, lime, and even blood and horse dung were often mixed in with the clay to form a hard, solid, long-wearing surface.  Scientific analysis of the clay floor samples found in the Montpelier cellar further revealed that the floors had been installed in multiple layers and that crushed bricks and lime had been added to the clay before it was compacted.