Downtown Seattle’s Avalara Hawk Tower, also known as 255 King, features Vitro Architectural Glass’ Solarban 67 glass with ICD HIgh Performance Coatings’ Opaci-Coat-300 coating on the spandrel, creating a harmonized aesthetic. Photo: Tom Kessler, courtesy of Vitro Architectural Glass

When discussing exciting glass industry trends it’s not often that spandrel comes up in conversation. It’s straightforward and steady. However, as technological advances and aesthetic preferences change vision glass, so, too, must the spandrel evolve.

Design decisions surrounding spandrel glass usually go one of two ways: standing out or blending in. Several paint companies, fabricators and glass manufacturers are focusing on improving the harmonization between vision and spandrel glass as architects increasingly prefer that aesthetic.

A Change in Vision

A building with spandrel glass that blends in with vision glass is not a new concept, but it has become more challenging in recent years according to Jeff de Waal, AGC Glass Co. North America’s architectural sales manager for Canada. He says that in the 1990s, reflective glass was incredibly popular, making it easier to achieve a closer match between vision and spandrel glass.

Today, architects largely have moved away from reflective glass in favor of high visible light transmittance which, de Waal explains, is harder to match with opaque spandrel.

“We’ve gone so far that the glass almost starts to look black with the absence of reflectivity. It makes it a challenge to match,” he says, adding that the difference in light transmittance creates different conditions between the two parts of the façade.

Michael Saroka, COO of Goldray Glass, based in Calgary, Alberta, says that harmonizing spandrel colors with vision glass is a decades-old concept, but one thing making the process more difficult is the addition of low-E coatings. He recommends using the same low-E coating on the spandrel and then opacify it to keep the reflectance the same across the vision and spandrel glass.

“You don’t use the low-E coating for its solar properties on spandrel but as a design feature to match the vision glass,” he says, adding that this does cost more than omitting the low-E coating on the spandrel.

Evolving Spandrel

Garth Tait, sales and technical support specialist for Hartung Glass Industries in Seattle, says that he’s seen a demand for harmonizing colors since the company began offering spandrel glass. However, as projects have gotten larger they are seeing more volume.

“Over the years we’ve definitely seen a growth in spandrel insulating glass units (IGUs). Spandrel used to be monolithic shadow boxes. It wouldn’t even have a coating on it. Now we’ve seen a shift to insulating with low-E coatings for the harmonizing aesthetic,” says Tait. “As architects are designing more all-glass façades, we’re seeing more spandrel to cover up the structure that was typically exposed before. As we go into more curtainwall, there is going to be more spandrel.”

Finding Harmony

Glass industry companies are finding ways to increase the harmonization between vision and spandrel glass. At Goldray Glass, Saroka says the company uses a device to aid in color matching.

“When harmonizing spandrel you’re looking for the reflective color of glass versus transmitted. Reflected color is black with a bit of a blue tint,” he says, explaining that Goldray uses a spectrophotometer to identify the reflected colors. “[The spectrophotometer] can get the reflective color so that you can measure it. Then it’s like matching any other color. Sometimes it requires trial and error until you can get an acceptable match.”

To better the chances of matching spandrel with vision glass, de Waal suggests increasing the reflectivity of both, and adds that architects should view samples with reflectance or even request a mock-up if they’re concerned about how it will look. He says architects often choose the vision glass they want and then ask what they can do with the spandrel.

“We listen to what they’re trying to achieve and then make recommendations,” he says. “Before we make any recommendations we ask as many questions as we can to understand the architect’s vision and how they want the building to look and perform … We’re careful about adhering to an architect’s vision because the aesthetic is their signature.”

The spandrel color should simulate the appearance of the vision glass, which is impacted by the color of the building’s interior. de Waal says that a light gray spandrel could match the vision glass of buildings with light or gray interiors; misty white could simulate blinds behind vision glass in buildings that often have the blinds down.

AGC’s new Lacobel T product is glass with the enameled paint baked into the glass when tempered. de Waal explains that the paint becomes more durable when baked into the glass rather than being painted on after it’s tempered. He adds that it can complement the vision glass if the spandrel uses the same glass.

To read the full article, which originally appeared in the September 2019 issue of USGlass magazine, click here.