The proper size of crown molding depends on the height of the ceiling. The height of the molding should be bigger for higher ceiling heights. For example, if a ceiling is 8 feet high, use crown molding that is 2.5 to 6 inches.Continue Reading
This Old House recommends that crown molding for a 9 foot ceiling should range between 3 to 7.5 inches in height. If a ceiling is 10 feet high, the molding should be 3.5 to 8 inches in height.
The Ancient Greeks used molding based on the shape of the ellipse, parabola and hyperbola. The Romans continued this tradition defining spaces with molding by updating the shape to the more modern half-round and quarter-round shapes. Both the Greek and Roman shapes are still the standard in present time. They are considered to be the building blocks of interior ornamentation.Learn more about Carpentry