What's new in sliding glass doors? A primer to help you glide into the right model

Sunset, August, 1999 by Don Vandervort, Barbara Boughton

Perhaps no single architectural feature is more emblematic of Western living than the sliding glass door. For more than 50 years, sliding glass doors have opened our homes to generous natural light and views, simultaneously giving us easy connections with decks, patios, and gardens.

Contemporary sliding, or "gliding," doors have come a long way since yesteryear's aluminum sliders, infamous for their stark appearance, sweating frames, and cold glazing. Today, a new generation of high-quality models offers energy efficiency, durability, safety, and contemporary style.

Size and style

Sliding doors come in a variety of sizes. In addition to the standard 6-foot, 8-inch height, they're made 6 feet, 11 inches tall or even 8 feet tall. You can also buy three- or four-door-wide configurations that are as wide as 16 feet. And sliders are made with one fixed panel and one sliding panel, or with both panels sliding. Most manufacturers extend your design options by providing matching rectangular and roundhead transom windows.

Some large manufacturers offer several sliding-door lines with a range of prices. You'll find doors that have wide rails and stiles (horizontal and vertical framing elements) like French doors, and doors with thinner rails and stiles that maximize glazing.

Some companies offer top-hung insect screens that are easier to use than sliding screens - they roll on a top rail instead of the bottom. With these, dirt, leaves, and debris along the bottom glide rail are much less likely to interfere with smooth operation. (For more on sliding screens see "Screen News," page 122.)

Doors are available through home improvement centers, lumberyards, and millwork shops. When you buy a sliding door system, be sure all components are from the same manufacturer. Check the warranty, and follow installation and care instructions. And last, buy quality: A well-made door will return your investment with easy care, smooth operation, energy efficiency, and great looks for years to come.

The popularity of wood

Although conventional aluminum sliders remain popular, other materials have given the genre a boost. According to Julie Ruth, vice president of codes and regulatory compliance for the Window & Door Manufacturers Association, "The wood patio door has grown tremendously in popularity."

Most high-quality wood sliders are milled from clear fir or clear pine by large window and door companies such as Andersen, Marvin, Pella, and Pozzi. Because wood is vulnerable to moisture and sun, it must be given a durable finish. For exceptional durability, many manufacturers protect the exterior sash and frames of these doors with vinyl or aluminum "cladding." Clad doors offer the best of both worlds - excellent durability outside and the natural warm look of wood inside.

Vinyl and aluminum cladding each have advantages and drawbacks. With vinyl, the color permeates the material, so scratches don't show. Aluminum will scratch, but it is tougher and available in a wider variety of colors. Neither

type will rust or rot.

With basic accessories, a 6-foot-wide clad-wood slider costs about $800 to $1,400; an 8-foot-wide door is $1,000 to $1,800. Installation will cost another $350 to $1,100, depending on exterior siding repair needed and the general complexity of the job. Of course, there are economies of scale: The more doors you install, the better the deal on both materials and labor.

You can also buy wood sliders factory-primed or prepainted in standard colors; some manufacturers will custom-paint them for a premium. For a dual-glazed, solid-wood door that isn't clad or painted, you'll pay about $750.

Other materials

Fiberglass and steel are particularly durable door materials. Both are made to simulate the look of wood, but fiberglass does this more convincingly than steel. Factory-primed fiberglass doors can be painted or given an opaque wood stain. A 6-foot-wide door costs $800 to $1,000. A 7-foot, 6-inch door with three panels costs about $1,300. Steel doors are rugged and typically cost $100 to $200 less than fiberglass.

Other alternatives are made of a polyurethane foam insulation core - offering six times the energy efficiency of wood - faced on both sides with vinyl or aluminum. These typically cost $400 to $1,500 for a 6-foot-wide door.

All well-made nonwood doors are designed with thermal breaks (separations between indoor and outdoor surfaces that block the conduction of heat or cold.)

Glazing options

Of course, the largest part of a sliding glass door is glass. To make a door truly energy efficient, high-performance glazing is key. Fortunately, this is standard with most high-quality sliders. You'll find double-paned glass with low-E (low energy) coating and, in some cases, argon gas filling. Low-E reduces heat transfer and protects against ultraviolet damage; argon gas filling provides greater insulation.

Some manufacturers let you specify the glazing you want when you order. Where sun-caused fading or damage can e a serious problem, you may want to opt for glass with a solar bronze or solar gray tint to reject ultraviolet rays.