Trim is a universal word that applies to any type of wood molding that dresses up walls and ceilings. Trim also has a very practical use, in that it can be used to hide joints, gaps, and other imperfections on surfaces. But most people add trim to their rooms because it is a bold design statement. White trim--painted glossy or semi gloss--is an effective accent against a field of darker colored walls.
Now, we said that trim is wood. That's not completely true. In recent years, plastic polymer has emerged as a strong contender to wood's longstanding place as the material of choice from which trim is made.
Wood tends to be a bit cheaper than the plastic polymer type, but it is usually heavier and more difficult to nail through. However, polymer trim has few imperfections--unless you simply bought an already-broken piece of trim at the hardware store. On the other hand, wood trim can often have many imperfections which do not show up until you try to drive a nail through it. The strongest point for plastic polymer trim: it does not shrink, like wood does.
Following are six different types of major trim that you might find in houses today.
Crown molding is found at the intersection of walls and ceilings. It is installed typically at a 45° angle, with a hollow space behind it.
Baseboards are the second most common type of trim found in houses. Baseboards range from the very narrow type all the way up to 6 inch-wide baseboards found in many older houses. Again, baseboards dress up a room and serve as a defining line at the bottom of the walls. However, baseboards also hide gaps between the bottoms of the walls and the flooring.
Casing is the trim that defines the area around window and door frames.
Chair rail is a horizontal piece of trim typically 3 feet from the floor that originally served the purpose of protecting walls from chairs! Today, it’s used more as a type of decorative element.
Picture rail is basically chair rail that is much higher on the wall. Less common than other types of trim, picture rail traditionally served the function of holding the hooks for hanging pictures with wire.
Wall Frame Molding
Wall frame molding is not common. You may see wall frame molding in more upper-end houses. It is a purely decorative wall element. The most common use is when you find four pieces of molding assembled to create the look of a picture frame.