Floor Molding

• The least expensive wood molding to add to the joint between the floor and the wall is quarter round. It serves the purpose of hiding the ugly joint. Adding base molding that ranges from 2 to 6 or even 8 inches to that quarter round adds a look of luxury to the room. The trim is flat on the back side and may be either flat on the front (as in Arts and Crafts homes) or shaped into ridges for more visual impact.
  
  

Cove Molding

• Cove molding, which creates a more interesting transition from the wall to the ceiling, is not flat on the back. It is curved so that it fits snugly against both the wall and the ceiling. It, too, can range in height, from a couple of inches to a multilayered trim of 8 inches or so.
  
  

Chair Rail

• Chair rails divide the wall into two sections, and are usually placed about 36 inches from the floor. This molding is flat on the back side and tapers from the center down to both sides. Home owners often treat the section above and below the molding differently. For instance, they might use two different colors of paint, or paint and wallpaper or two complementary wallpapers.
  
  

Wainscoting

• Sometimes wainscoting is added below the chair rail. It is wood paneling trimmed with various amounts of molding, ranging from simple half-round molding to fancier multilevel flat-backed molding.
  
  

Window and Door Molding

• All windows and doors need trim to cover the place where they join the dry wall. The trim used is flat on the back and generally ridged (except, again, for Arts and Crafts homes), with the thicker part at the outside of the molding. Occasionally, the corners are trimmed with a separate molding piece, often a bull's-eye or a simple four-petaled "flower" motif.