What is "tadelakt"

Tadelakt (tadla:kt) is a waterproof plaster surface used to make baths, sinks, water vessels, interior and exterior walls, ceilings, roofs, and even floors. It is made from lime plaster, which is rammed, polished, and treated with soap to make it waterproof and water-repellant. Tadelakt is labour-intensive to install, but durable. Since it is applied as a paste, tadelakt has a soft, undulating character, it can form curves, and it is seamless. Pigment can be added to give it any colour, but deep red is traditional. It may have a shiny or matte finish.