takes up to a year after the building Interior Trim Part II by Gordon F. Tully Setbacks Whenever a setback or shadow line occurs in a building, make sure its width does not vary too much along a piece of trim. Quantifying "too much" is a matter of judgement and experience; ideally the variation between the minimum and maximum setback should not exceed a 12 ratio, and 1:1.5 is much better. A classic example of this principle occurs when a 1/2-inch quarter-round is placed on top of a 5/8-inch or 9/16- inch baseboard. As the quarter-round base cap moves in and out with the wall, the exposed "shelf' in front will vary from as little as 1/16 inch to as much