Final answer:
The rule for window casings and doors in relation to baseboard height is that the casing or trim around the window or door should be installed first, and the baseboard should be installed after to create a seamless transition.
Step-by-step explanation:
The rule for window casings and doors in relation to baseboard height is that the casing or trim around the window or door should be installed first, and the baseboard should be installed after. This is because the baseboard should overlap slightly with the casing in order to create a seamless and visually appealing transition between the two elements.
For example, if you have a window with a casing that has a thickness of 2 inches, you would want the baseboard to be installed so that it slightly overlaps with the casing. This way, when you look at the window from the side, there is no gap between the baseboard and the casing, and it looks like one continuous trim.
Similarly, the same rule applies to doors. The casing should be installed first, and then the baseboard should be installed against the casing, overlapping slightly to create a clean and unified appearance.