Over most surfaces (prepped latex-painted wall), only 1 coat is needed. If installing white dry erase paint on a colored wall or surface, a white primer will need to be applied first to seal the color in. Also, additional layers may be required on non-smooth or absorbent surfaces. The number of coats is determined by the substrate and the thickness of each coat to achieve the matching coverage area. Just a single even coat is all that is needed on most smooth painted walls. Keep the coverage even ensuring that all areas are covered to a thickness that protects the surface. Some applicators may retain more product than other applicators affecting spread rates. A good way to know the coat thickness is if it does not leave runs or drips and you are covering about 3 square feet per ounce. Just simply apply the number of coats that it takes to use all of the product stated for the coverage area that you want. For example: for 50 square feet of coverage uses about 17 ounces (50 square feet / 3 ounces per square foot = 16.7 ounces) of applied dry erase coating. Normally 3 coats. The number is usually determined by the thickness of each coat applied. Also, some applicators may retain more paint than others.