Today’s Prefinished Doors Combine Ease of Installation and Long-Lasting Beauty

By Kenn Busch

Here in North America, we expect a lot from our entry doors. And with the last decade’s changes in builder labor and homeowner life-styles, we can add ease of installation and (very) low maintenance to the list.

“People are now looking for doors they can install and not have to worry about maintaining for a few years,” says Andrew Hess, vice president of the Entry Door division of Lumbermen’s Inc. in Grand Rapids, Mich. “The labor force has changed tremendously, and that continues to be our biggest struggle. During the downturn we lost a lot of people in the building and distribution side, so doors now need to be easy to install and require few callbacks.”

Prefinishing their wood and fiberglass doors was the first step, easing the anxiety many homeowners have at the thought of staining or painting their own doors. At the same time, builders were having issues with contractors and painters who didn’t under-stand how to properly finish door frames, leading to peeling paint—the biggest cause of multiple and expensive callbacks.

“This is why, 90 percent of the time, if you’re getting a prefinished door, you’ll get a prefinished frame and trim package as well,” says Hess. “It takes an additional step out of the process for the home-owner and greatly reduces callbacks. If the builder installs a prefinished door system, they won’t have the issues that require them to send out a painter, where they have no control over the end result.”

Hess says the new generation of rigid vinyl-wrapped door frame components has been the biggest leap forward in prefinished door frames.

“This has made a huge difference, because it used to be a primed jamb, or just a raw wood jamb where you see a lot of rotting and paint peel,” he says.

Prefinished Frames: A Primer

A prefinished door frame can take two basic forms. One is a co-extruded poly-fiber system made with PVC and wood flour. The other is based on finger-jointed pine, coated with primer or primer and paint, clad with aluminum or wrapped with a PVC film.

Initially, the idea behind prefinishing door frame components with primer was to create a vapor barrier, protecting them from the weather and elements for a period of time – just until they can be installed and painted.

“Because a primer has to be open and porous to accept a topcoat, it will fairly quickly wear down from the elements,” says Kevin Karrip, vice president of G-M Wood Products in Newaygo, Mich. His company makes Dura-Tech vinyl-wrapped jambs. “If it’s been out in the weather for three or four months, you should re-prime it. Primer is really a vapor barrier, because raw wood will draw in moisture immediately.”

Most suppliers used to sandwich their Douglas fir blocks between layers of felt to prevent denting or telegraphing through the steel skins in the book press. G-M developed a method of drying and machining locally sourced pine blocks so they didn’t require felt faces. This caught the attention of some steel and fiberglass door manufacturers and led to requests for other high-tolerance components—namely, door frames and brickmolds.

Taking on these new products required the company to develop further expertise in drying, fingerjointing and moulding available wood species. At that time, 90 percent of all exterior door frames were sold primed.

“We went through nine different primer formulations until we found one able to withstand the elements for 180 days, because here in the Midwest, doors that were delivered or installed in the fall might have to wait until spring to be painted,” says Karrip.

A second and significant cause of paint peel on door frames is wood rot that usually begins at the bottom of the jambs. To address this, some suppliers spliced in a section of composite material, which is effective at resisting rot but a poor substrate for primer adhesion.

“We found Alaskan yellow cypress to be a better alternative,” says Karrip. “Its primer adhesion properties are similar to pine, and it’s naturally highly water-resistant. Even unfinished, cypress can last for hundreds of years.”

An end-seal on the bottoms of the jambs completes the company’s Dura-Frame systems.

Co-extruded poly-fiber components were the next step in the evolution of prefinished door frame mate-rials. They’re durable and weather-resistant, paintable and stainable.

Vinyl-Wrapped Frames

“For all its benefits, a co-extruded frame does have two drawbacks when compared to wood-based frames,” says Karrip. “It’s twice the cost of primed wood. And because it is less rigid, it’s tough to maintain straightness once installed—it doesn’t expand and contract like the wood components it’s mounted to.”

Even so, Karrip says the market loved the impact-, scratch- and UV-resistance of the PVC surface. If that level of quality could be wrapped on a wood substrate, the resulting frame would represent the best of both worlds.

“We felt we already had the very best substrate in the market, and we wanted the very best PVC film that we could offer,” says Karrip. “And if we couldn’t find a film that met our standards, we were willing to work with someone who could develop it.”

Karrip says he found that American Renolit already had an exterior-grade MLA film that was impact-resistant, scratch- and UV-resistant, thermally stable, and comes with woodgrain, stipple and smooth embossing options.

The company chose a rigid 12 mm film for what would become its Dura-Tech product line. But choosing the right surface film was only half the battle. Finding a profile wrapper that would take the time to truly under-stand how best to bond the film to the substrate was a bigger hurdle.

It found a good solution with Premier Profile Lamination (PPL) in Youngstown, Ohio.

Minimizing Scrap

For Robert Kingston, the founder of PPL, the formula is simple: reduce scrap and seconds.

“Wood is a living, breathing material, far from perfect,” says Kingston. “To properly laminate it, you have to somehow turn it into a perfect specimen. This is where we work closely with our customers to help them reduce rejects from 30 or 20 percent down to two percent.”

The result is components able to withstand rigorous testing standards– Kingston’s own.

“There’s no industry-approved test for this product, so I’ve adapted an ASTM test for fingerjointed wood,” he says. “I take samples from every production run and heat them for 20 hours, boil them for four hours, heat them again for 30 hours and boil them for another four hours. If a sample can withstand this heating and boiling cycle two times, it’s probably going to be there forever.”

Kingston also conducts accelerated and real-time weathering tests in his plant and archives a sample from every production run in case a frame component ever fails in the field.

Finishing Touches

Once wrapped and blessed by PPL, the frame components head for distributors to be assembled and mated with entry doors. White PVC foils are often left unfinished; many are also painted or stained to match the door with which it’s being mated. Tan foils are always finished.

In recent years, black and darker paints have become more popular. This means moderate to significant heat absorption and buildup, degrading the finish and possibly the wood frame itself.

G-M and PPL found a solution to this problem, too: wrapping the 12 mm PVC with a 7 mm multilayer acrylic and polyvinylidene fluoride film in an array of woodgrain finishes or colors, including black.

Kenn Busch is a journalist and architectural photographer based in Madison, Wis., who counts on American Renolit as one of his clients.

To view the laid-in version of this article in our digital edition, CLICK HERE.

DWM Magazine

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