Scale and Proportion
In a well proportioned design, the baseboard is taller than the Chair Rail, and the Chair Rail looks more substantial than the Door Casings. The molding used for the Applique itself is the smallest of the three. All the materials used should be scaled according to the size of the wall they will be applied to.

Balance
The goal is to achieve a symmetrical arrangement, if a wall can hold 3 wall frames; you can make the middle one wider. If a wall can hold 5 frames, make the middle and two end frames narrower. You can use both of these approaches on some walls when doors or windows dictate more or fewer frames.

Intervals
An Interval is the area within an individual wall frame, defined by the frames outside dimensions. Interval height and width can vary as needed to accommodate doors, windows, fireplaces, cabinetry and any other element that may intersect a wall. By holding the margins constant and allowing the dimensions of the intervals to expand and contract in response to wall runs, you can maintain an overall sense of proportion, balance and continuity.

Margins
Margins are the spaces above, below, and in between wall frames. A margin of 2" - 3 inches is recommended. With that said, it is generally recommended that no margin should ever be less than 2" inches. The margin on the top and bottom should be the same throughout the installation except when installing under windows or narrower sections of wall. When a space is too narrow to insert an Applique, leave it empty. When installing under a window frame, the applique width should line up with the outside edge of the window casing. In some situations this will mean that the vertical margins between the appliques will vary greatly from the rest of the installation.

Interval Width Worksheet
Use the information provided in the following worksheet to determine the width of your Applique intervals. First estimate how many intervals would fit each wall yet be equivalent to each other. For example if you had a 12 x 18 foot room, you might make an estimate based on 36" wide intervals. The 12 foot wall would have four and the 18 foot wall would have 6. Of course the actual sizes will be smaller because you have to account for the 3" margins.

Follow these steps to determine the Interval widths

1. Width of Vertical Margins Multiplied by Number of Vertical Margins
2. Length of Wall Run Minus (answer of step #1)
3. (Answer for Step 2) Divided by Number of Intervals
4. Total from step 3 will give you the average Interval Width.

You should continue to modify estimates for each wall run until you are able to determine the closest possible sets of interval widths for all the walls in the room. This will allow you to create symmetry throughout the room.

Determining Vertical Dimension
In a room with either an 8 or 9 foot ceiling, the recommended Chair- Rail height is 36 or 42 inches respectively. A 60 inch height can also be used if you are looking to make long vertical appliques, this should only be done in a room with a ceiling of 9 feet or more. Avoid heights between 36 and 60 inches, or the room will appear cut in half horizontally.

Working around Electrical Outlets
Electrical outlets may not be the only thing you may have to deal with; it could be Cable, Phone Jack, Central Vacuum outlet or a variety of other things the modern world throws at us. If one of the vertical sides of the Applique falls on an outlet, either move the outlet or install an outlet box extension and spacer frame into which you can butt the side of the applique. An outlet extension can be purchased at any big box store. You can create a frame around the extension, to which the applique can be butted, this will finish the outlet nicely.