United States, the "comb" is commonly referred to as the "scratcher". The next layer is called the "brown coat" or leveling coat. It is leveled with tools called "Darbys" and "Rods", scraped smooth, and floated to provide a nice even surface onto which to apply the color coat. It is then allowed to dry (cure) for 7–10 days minimum to allow "checking" (shrinkage) to take place. The final layer is referred to as the "color coat" or "finishing coat", and is typically 3 mm (1/8") thick. It usually consists of clay with no fiber and sand added. The color coat material was found in certain areas, red, green, white with mica and other colors, the material was gathered, made into a uniform consistency, water added, applied to the walls in multi layers until the desired surface was acceptable. The process in Spanish was known as, 'alisando'. Advantages and disadvantages of earthen plaster Earthen plasters are less toxic and energy intensive than many other wall coverings, which makes them appealing to the environmentally conscious. Earthen plasters are also easily repaired and inexpensive. They resist water penetration but are permeable to water vapor. However, earthen plasters are often more labor-intensive than other forms of wall covering. If the mix does not have the correct component proportions, then many other problems may occur, such as dusting and cracking. Earthen plasters are not approved by all local building codes, and some require the use of cement stabilizers or asphalt emulsion. Earthen plaster is a rare wall covering in the developed world and there is a dearth of local experts for construction and repair. See also Building construction Exterior Insulation Finishing System Green building Natural building Plasterwork Tadelakt Wattle and daub Zellige Notes Sources McHenry, Paul Graham Jr. Adobe: Build it Yourself. The University of Arizona Press: Tucson. 1974. Norton, John. Building with Earth: A Handbook. Intermediate Technology Publications Limited: London 1997. Soil-based building materials Plastering