They cost about $50 apiece more than wood or steel, but Holiday Builders in Melbourne, Fla., installs smooth-surface fiberglass entry doors on all of its single-family homes.

Wood doors, says corporate purchasing director Scott Clark, can warp and rot in Florida's steamy climate. And steel doors, he notes, can dent and rust.

Indeed, because smooth fiberglass entry doors resist dents, dings, rust, and warping, they have become the fastest-growing segment of the entry door market, says John Kufner, general manager of entry products for manufacturer Therma-Tru. Fiberglass entry doors, including smooth and textured products, claim 15 percent of the market, up from 10 percent at the turn of the century, shortly after smooth fiberglass was introduced. This makes smooth fiberglass doors one of our top innovations since 1990, the year BUILDING PRODUCTS was founded.

Production builders, partial to sturdy, affordable steel doors, typically turn to more expensive look-alike smooth fiberglass to keep construction costs down once they tire of replacing steel units scratched and dented during deliveries of appliances and other heavy building products to the jobsite. Clark says that's what swayed him to switch three years ago. Since then, he has used smooth fiberglass doors on 8,000 homes.

The climbing price of steel during the past couple of years has narrowed the price gap between steel and fiberglass, luring more converts to the composite doors, which mingle fiberglass, resins, and fillers to form panels that manufacturers claim are 10 times more resistant to dents than steel and about 10 times less likely to rust, even on a beach house.

Most manufacturers' fiberglass doors are firerated and some even pass Dade County, Fla.'s stringent tests for impact resistance during hurricanes.

Still, some builders consider smooth fiberglass doors a commodity product best reserved for low-priced tract homes.

One builder says printing his company's name in an article about smooth fiberglass doors could ruin the firm's reputation as a high-end builder.

“It's not decorative enough for our communities,” says the builder, who notes he puts smooth fiberglass doors only on lower-end and multi-family homes. “When you go to a raised-panel, textured product, fiberglass is more decorative.”

But John Monfore, product marketing manager for exterior doors at manufacturer Jeld-Wen, says smooth fiberglass doors are penetrating the move-up market.

He points to an increasing interest among builders in Atlanta neighborhoods, where $600,000 to $700,000 homes show off painted steel doors. Even there, he says, “Fiberglass is starting to take away from steel.”

Kufner adds that Therma-Tru distributors are selling smooth fiberglass doors to more custom builders and remodelers. But the product's mainstay, he concedes, is production housing, especially in communities designed for families.

And in the remodel market, notes Kufner, “Families with children are driving the use of smooth fiberglass.”

Monfore predicts that nationwide, smooth fiberglass will claim up to 20 percent of the entry-door market within five years as the largest production builders opt to install them on nearly every new home.

Furthermore, after selling smooth fiberglass almost exclusively for front doors, manufacturers say that its popularity as a patio door product is growing. “In five years, it might take over the patio market,” Kufner says.

Patio doors with smooth fiberglass mingle a substantial amount of glass with a fiberglass frame.

Clark, whose average home sells for $125,000, says using smooth fiberglass in place of steel or even wood separates his company from his competitors'.

“We like to think of ourselves as being a cut above” the others, Clark says. Indeed, Holiday Builders promotes its use of fiberglass doors as one of the benefits of buying its homes, and educates its customers about the product's perks compared with steel.

Therma-Tru. In a test against steel counterparts, the Smooth-Star fiberglass door was more than 10 times more resilient against dents and rusting, even in coastal areas, the company says. For builders, this durability can mean fewer call-backs, saving the builder time and money. The maker also claims the door discolors at a slower rate than its competitors' products. 800-843-7628. www.thermatru.com.

Masonite. Belleville fiberglass entry doors, offered in wood-grain textures and paintable smooth designs, come with a range of ornamental glass options and a square-edge structure. According to the maker, the doors do not rust or dent and are impervious to cracking and distortion. 800-663-3667. www.masonite.com.

Peachtree. As part of its Newport entry door line, the manufacturer offers the panel-style Duo-Choice in straight, smooth fiberglass, or with a smooth exterior and textured interior. The smooth fiberglass panels, which can be painted, have a maintenance-free sill that withstands moisture and rot, the manufacturer says. Glass sections come in seven patterns. 800-732-2499. www.peachtreedoor.com.

Kolbe & Kolbe. Made in textured and smooth versions, these fiberglass entry doors feature a high-insulating core made without ozone-depleting carbons. The composite material will not warp, and the color is uniform throughout, the firm says. Along with an assortment of decorative glass inserts, the units are available in five stained colors and 22 painted colors, as well as custom options. 800-955-8177. www.kolbe-kolbe.com.

Pella. This line of fiberglass doors, including the PowerHouse version featured here, comes in smooth, fir, and oak-grain varieties. The material will not deteriorate, the firm says, and the core insulates five times better than the typical wood door. For all doors, the jambs are constructed above the sill to avoid water damage. 888-847-3552. www.pella.com.

Jeld-Wen. Because they contain more than twice the fiberglass as the industry standard, Premium fiberglass doors have exceptional durability, resist harsh winds, and increase the security of a home, the maker says. The doors are available in 32 styles, including wood-mimicking mahogany and smooth surface. Internal stiles and rails consist of AuraLast real wood, which has been treated to ward off decay, water absorption, and termite infestation. 877-535-3462. www.jeld-wen.com.