This was a workshop that I taught, covering to the use of hydraulic lime mortars incorporating earth. This is a technique known in France as “engobe” and in Spanish as “brunido”, which we finished using techniques from Moroccan Tadelakt work.
The surface to be covered (a circle of 82 square meters) was prepared with a base layer of limestone hardcore and sand. Then the design was drawn out, and the area divided into three concentric circles, intersected by two crosses (producing an eight-pointed star.)
The design was marked out with offcuts of marble from a nearby marble workshop, and we ensured that all the marble was level as these markers were used to ensure a level floor. Each segment of the design was then filled with a first coat of lime mortar, to a level lower than the the marble edges. A second coat was applied to each segment, individually coloured using a mixture of earth and lime putty, similar to Tadelakt.