trim

The rule of thirds. Installing a chair rail, with or without wainscoting, will divide the vertical plane — the walls — into multiple areas. If you want to make the room feel taller, place the chair rail one third of the way up from the floor.

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All together now. A well-trimmed room is something special. Its baseboard, casings and crown all relate to each other in their style, proportions, sizing and finish. In this example, the baseboard appears to follow the 7 percent guideline: The casings are about half the size of the baseboard, and the crown looks to be just slightly smaller than the baseboard. There's no doubt that the trim for this room was conceived as part of the overall design.

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As always, this isn't a hard and fast rule. Casings that equal the dimensions of the baseboards certainly can work quite well.

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For casings, 50 percent is good. Generally, vertical trim elements such as door and window casings should be smaller and have less heft than baseboards. So I've found that a good rule of thumb for sizing window and door casings is to keep them at about 50 percent of the height of the baseboard.

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The 7 percent solution. When sizing a baseboard in a traditional-style home, a good starting point is to use a ratio of 7 percent. So if your ceiling height is 8 feet high, try a baseboard that's about 7 inches tall.

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Skinny trim. Please don't settle for 3-inch baseboards and 2¼-inch casings. Trim has so much to offer and can really make a room special. Solution (shown): Think about different profiles and go for the larger sizes. Doing so will add a richness to your rooms that you didn't think was possible.

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