Plastic, wood composite, and metal trim products will see above-average gains through 2008, according to a study from industrial market research firm The Freedonia Group. The study found that although wood materials are still dominant, with two-thirds of total demand in 2003, they've been losing ground in recent decades to composites and other materials. This trend signals a boon for urethane and PVC trim manufacturers.

Among the advantages of urethane and PVC molding and trim is that they can be produced in longer lengths than wood usually can. It's difficult to get a completely clear piece of wood in a long length, explains Greg Wolf, director of marketing for Fypon, a urethane trim manufacturer. “People are going with higher ceilings and doorways; the trend is with larger molding, which tends to have more of a massive look. In those situations, the urethane moldings have an advantage.”

Wood trim substitutes help eliminate problems with decay and damage to exterior moldings, reports Wolf, even in a historic restoration. Plus, he notes that wood trim “can be easily replicated in urethane using a mold that's the exact match.”

Sherrie Towne, marketing specialist at Focal Point, a polystyrene trim manufacturer, agrees. She says that while more complicated decorative details and layers can make wood trim pieces heavy and difficult to work with, polystyrene trim can achieve the same intricate results yet remain incredibly lightweight. “If you're trying to achieve a deep crown molding, you have to create a lot of layers with wood,” says Towne. “But with polymer, you can do that with one, lightweight layer.”

Ease of installation is another factor in polystyrene's popularity, according to Towne. “If you've got a wood build-up that's 5 to 10 pieces, that's very costly and labor-intensive. [With] so many of the polymer styles that are offered, you can glue them or pop them in place with blocks.”

Wood retains one major advantage: Polystyrene has to be faux-finished to look stained. The desire for a stained, wood-grain look is a big reason some people will choose wood over plastic trim, says Wolfe. “There's still a place for wood molding, especially when you want grains.”