Colossal Sliding Glass Doors

By Eric Reinholdt

Large sliding glass doors blur the boundary between inside and outside.

Architect Philip Johnson famously remarked, “I have very expensive wallpaper,” referring to the four see-through walls of his Glass House, completed in 1949. Even today transparency defines modern architecture. And our desire to connect our interior living spaces with the outdoors has only increased in recent years. 

Establishing these connections, though, without completely sacrificing a building’s thermal performance has been very difficult. But the demand for spaces that open completely to the outdoors has spurred the development of larger and larger thermally efficient doors. 

If you’re contemplating your own colossal openings to the outdoors, here’s what you’ll need to consider.

1. Materials

Material options for these doors essentially fall into one of three categories: metal, metal-clad wood or all wood. 

Metal (Aluminum, Steel, Bronze, Cor-Ten, Stainless Steel)

Metal frames can withstand higher loads per given cross section than their wood counterparts. This makes metal an appealing choice if your preference is to reduce the amount of visible frame and obstructions between interior and exterior. Stronger materials yield narrower sight lines; that’s one of the big selling points for all metal frames. 

Watch for: With metal it’s especially important to select a thermally broken frame. These are frames constructed to isolate the exterior metal from the interior metal to prevent heat transfer and condensation.

Metal finishes. Selecting the finish is an important decision not only for aesthetics but also for durability. Finishes vary based on the metal chosen. 

The most common treatment of metal door components is a painted finish. Various methods are used depending on the manufacturer, substrate and final finish desired, but the basic idea is to cover the bare metal with a durable, UV-resistant, weathering surface. You want a finish that will endure many years of exposure without fading or chalking (or maintenance). Painted finishes are available in almost any color and come with the longest warranties.


The beauty and warmth of wood, especially for interiors, is hard to match. Used on the exterior, it can be equally beautiful if maintained properly. Therein lies the conundrum: We love the look of natural wood but don’t love the maintenance. Over time the elements can be particularly brutal on exposed wood doors even with the best marine finishes.

Watch for: The benefits. Wood can be sourced from sustainable forests, and the embodied energy is much lower than metal, which makes it an environmentally friendly option. Wood is naturally a poor conductor, so there’s less to worry about when it comes to thermal performance as compared to metal frames. 

The trade-off comes with reduced structural efficiency. This means the frame profiles, or sight lines, are heavier, permitting less overall glass area. But as this image clearly shows, this can be more than compensated for by stacking multiple panels end to end.

Wood finishes. All manner of finishes are available for wood: paints, stains, penetrating oils and clear coats. Paint conceals the wood and provide color. Stains allow the grain of the wood to show through by varying degrees. Clear coats and oils preserve the natural new-wood look. 

Describing each of these is beyond the scope of this ideabook; suffice it to say that wood doors are a long-term investment from a maintenance standpoint no matter which finish you select. Sanding and refinishing should occur on a regular interval: every two to three years on south- and west-facing doors, three to four years on north- and east-facing ones. Over the lifetime of the door, this will substantially preserve the investment.

Clad Wood

Fear not; there is a way to have both the look of natural wood with the durability and low maintenance of metal. Enter the clad door. 

Typically the exterior cladding is fabricated of painted aluminum, with hundreds of color choices (with long warranties), while the interior is constructed with the wood of your choice. Whether the wood should be painted, stained, oiled or given a clear coat depends on the interior material palette.

Watch for: Because the structure of the door is wood, you’re still limited by the beefier sight lines, but the lower maintenance more than compensates.

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Originally Published in Houzz

Mon Feb 17 00:00:00 PST 2014