Paint-Grade Interior Trim
Choosing molding that looks good and finishes well takes more thought than it used to.
Synopsis:Shopping for interior trim can be an overwhelming chore. The array of products made of different materials can leave even experienced builders scratching their heads. FHB associate editor Chris Ermides takes a look at today’s world of interior trim, including finger-jointed, medium-density-fiberboard, and synthetic trim products. Each style is profiled and includes a list of pros and cons. This article includes a sidebar about flexible moldings, which can be useful on curved walls or arched openings.
Magazine extra: Take a tour inside The New England Woodworking Company’s millwork shop, and learn how custom and replacement-molding profiles are shaped on their computer-aided cutting equipment.
If you’re reading this website, you probably love wood. Like it or not, though, when it comes to painted trim, the alternatives to solid wood can make more sense. Finger-jointed, medium-density-fiberboard (MDF), and synthetic trim come with primer coats applied at the factory, which saves you a load of time and trouble. But choosing among these three materials isn’t easy.
Finger-jointed trim is knot-free, but it can be pricey. MDF is inexpensive, but it can’t get wet. Synthetics come in complex profiles, but they require special adhesives. The look you’re after and the specific application (baseboard, casing, crown, or chair rail, for example) will figure in your selection, along with cost, workability, durability, and dimensional stability.
Moldings have a purpose
According to Brent Hull, a historic-moldings expert, interior moldings do two things. First, they define the major shapes and spaces in a room, like doorways, windows, and floor-to-wall and ceiling-to-wall connections.
The second thing moldings do gets at the heart of how to tell good-quality from poor-quality trim. When trim is on a wall, it refines a room architecturally. Profile design, detailing, and scale create the architectural style and tone of the space. But the visual impact is often a subtle, subconscious thing you might not immediately recognize. That visual impact is largely a function of how well defined the profile shapes are and how sharp the profile’s edges are. Hull pushes this point further, adding, “When you look at moldings once they’re installed, you should be able to easily read the shapes that make up the profile.”
Veteran trim carpenter and FHB contributing editor Gary M. Katz agrees: “Crisp, sharp edges create crisp, sharp shadowlines. The relationship between shadow and light is what defines an attractive molding profile, one that can be seen and enjoyed from up close or from a great distance.”
Sharp edges should form around transitions between the shapes that make up the profile. This is especially important with crown molding because it’s installed overhead and because light doesn’t hit it directly. If the profile is muddied with shapes that aren’t deeply, crisply cut, it will look like fuzzy lines against the ceiling.
It’s important to note, though, that the quality of a molding’s profile isn’t a function of the material it’s made from. You can find sharp or muddy profiles on moldings made of finger-jointed wood, MDF, or synthetics.
Finger-jointed trim is more stable than solid wood
Finger-jointed trim gets its name from the interlocking joint used to connect short boards together end to end. Typically made from various species of pine, finger-jointed trim is free of knots and other defects often associated with solid wood. It’s also less likely to cup because finger-jointed trim wider than 6 in. is made by edge-laminating narrower sections together.
In the past, carpenters complained that finger-jointed trim fell apart at joints or that joints telegraphed through finished surfaces. But according to the manufacturers and expert installers that I talked to, joints fail or telegraph because of poor quality control during the manufacturing process, not because of an inherent weakness in all finger joints.
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