Volume 8, Issue 8 - September 2007

Wide Open Spaces
How Opening Wall Systems are 
Making their Way into Mainstream Fenestration

by Ellen Giard

What’s one of the hottest trends in the residential market these days? Outdoor living. 

From kitchens to spas to overall entertainment, homeowners are looking for ways to connect to the outdoors. Thanks to innovations in glass and glazing systems, fenestration companies are poised to take a firm hold on this market trend. One popular fenestration option of late is the moveable/opening glass wall system.

These systems, which consist of large spans of glass panels, are designed to slide or fold open, creating a way to bring the outside inside. Operable glass walls, influenced by European design, have been available in North America for more than two decades. It’s been in recent years, though, that the systems have been making their way into North American construction at an accelerated rate. 

System Manufacturers
Nana Wall Systems, a manufacturer of opening glass walls based in Mill Valley, Calif., has been working with these wall systems since the mid-1980s. President Ebrahim Nana says his company, which began as a real estate developer, started to see a market for large openings in 1986.

“From 1986 to 1990 we imported a system from Germany and then from 1990 to 1996 we began making our own, and in 1996 we became partners with Solarlux [a German manufacturer],” says Nana. “I think one of the reasons we’ve been successful is because we started out with some experience with operable walls for the United States. Our German partner then helped us Americanize their German system.”

Another California company, Weiland Sliding Doors and Windows located in Oceanside, has been making sliding glass door systems since the 1990s and before that was involved in specialty woodworking. Sue Weiland, chief financial officer and one of the company owners, explains that the decision to begin making the sliding door systems was driven by customer requests. Bill Weiland, company founder, traveled to Europe to learn about the products and then brought ideas back to their operations in the United States. 

Solar Innovations Inc., located in Myerstown, Pa., began manufacturing operable wall systems within the past five years. But the company is not new to glazing products, as it has roots that date back to the 1950s and has manufactured a variety of fenestration products including conservatories, sunrooms, skylights and more.

“The reason we got into it was because we could not find a good exterior operable wall system that would meet our needs and our customers’ needs,” says Greg Header, president. “We had tried buying others but we found that we could design a better one ourselves.”

Why So Popular?
Nana Wall, Weiland and Solar Innovations all agree that the operable wall systems are fast-growing in terms of popularity and usage. Alison Blume, marketing manager for Nana Wall, says their sales have gone up more than 50 percent in the past few years. Header says they, too, have seen a great deal of growth.

“The operable wall is our fastest-growing line,” Header says. “In the past year we’ve grown as a company by about 25 percent and the walls alone have grown at a faster pace than that.”

Weiland adds that her company has seen “healthy” growth in the past few years, too.So what is it that has accelerated this growth? A need and desire to connect to the outdoors.

“What has lead to the growth of interest in our doors is the desire by homeowners to expand their living area to the outdoors," says Weiland. “These moving glass walls eliminate the typical barriers of a patio door by providing a seamless transition between the indoors and outdoors."

Nana agrees. “There’s a romance in being able to connect to the outdoors. These systems are like a convertible—it’s a regular car, but when the weather is nice you can open it up; then when it rains you close it and it’s as weather-tight as any other car. You get the best of both worlds.”

Another reason for the popularity is the shear aesthetics that come from large spans of glass.

“Architects will select something like this just for the aesthetics,” says Nana, who explains that his company’s systems are designed to have a minimal frame in order to maximize the view. “And all of the hardware is concealed,” he adds.

While operable wall systems are a hot item, they’re not likely to be found in any neighborhood subdivision. These are high-dollar products, commonly found in upscale, luxury homes, vacation homes and anywhere there’s a stellar view.

“It’s a novelty, though they are becoming more popular,” says Header. “It’s a smooth operator, they are sleek, well-designed and engineered. People like them because they can just push them aside and have more living space and a more open area.”

Nana says about 55 percent of their work is in high-end, single-family homes, but they also do jobs for high-end multi-family (as well as hospitality) applications, mainly in dining areas.

Manufacturers agree that cost, which can be as much as 50-percent more than a French door, is the main reason a customer may decide against using an operable wall. “Anything that can fill an opening is a competitive product,” says Steve Donner, general manager for Weiland Sliding Doors and Windows.

In order to maintain a competitive edge, Weiland says they emphasize the special features that the products offer. “Seamless transition as a result of a flush track with transverse drains; our large panels offer more glass and a better view. Also, the liftslide hardware enables the customer to open and close these large, heavy panels easily,” she says.

The Right Fit?
Opening walls and sliding door systems are not without challenges. Many requirements must be met to ensure the system works properly.

“It’s got to be weather-tight, it’s got to be secure and then it has to be easy to operate, not only when it’s new, but over time as well,” says Nana. “So we have adjustments and compensation features built into the systems. The adjustment features are there so if the building settles or the head sags [it can be fixed easily] without having to re-install the system.”

Header agrees that proper installation is critical.

“Because they [the systems] cover such a large space the header design of the home needs to be considered carefully,” says Header. “Deflection can also be an issue … because the doors are on a track you don’t want it to deflect too much. The weight of the system hanging above, as well as the weight of the room above, can make the header sag.”Weiland says that, because the system is an integral part of the wall, tolerances are a bit tighter than they are with traditional sliding doors, also requiring attention to detail. To ensure the systems are installed properly, manufacturers try to educate installers. Each manufacturer, for example, has developed an installation manual to guide installers through the process. In-house support is also available. Some manufacturers have a network of trained installers that they recommend are used whenever possible.

Testing is also Critical
“It is a way to prove your products’ capabilities scientifically,” says Jonathan McKee, project management supervisor for Solar Innovations. “With so many manufacturers in the market these days, it’s critical to set yourself apart by showcasing your products’ capabilities. Also, certain regions of the country will only allow you to sell or build in that area if you have the certification to do so.”

Weiland says her company tests every door in-house. “Because of the custom nature of the doors, each one is unique in size and configuration,” she says, and adds that outside testing has also been done on certain configurations. Having a product tested to meet certain requirements can also be a measure of confidence for the architects and customers.

“Our main market is reaching the architect, and architects want products that are tested so if, for example, there was a leak they could pass the buck,” says Nana. “It also gives customers confidence [in the] performance that they get.”

A poor-performing product, Nana explains, can be detrimental to the entire industry.

“Our worst nightmare is that someone sells a system so poorly designed that it creates a bad image for the whole industry,” Nana says.

What about concerns such as heat or cooling loss and pesky bug problems? If an entire wall in a house is made of glass some might think it could be a challenge to maintain a comfortable inside temperature. And, when that wall is wide open to the outside, it might also open the whole house to insects. While either scenario could happen, manufacturers have solutions for both.

Nana says one of his company’s main challenges is to spread the word that these systems are not just for warm climates. He explains that four of its 16 lines have NFRC ratings and Energy Star® ratings.

“It’s basically an all-glass wall so the efficiency comes from the glass that is used,” says Donner.

“Our doors are designed with a tight seal so they are made to be as energy-efficient as possible,” adds Mike Plevyak, vice president of research and development for Solar Innovations. “We also use the same commercial-rated system in residential applications that we do in commercial applications.”

As energy codes continue to become more stringent, sometimes it can also be a challenge to ensure the systems will comply.

“In California you have Title 24 (in the state’s building code) so if the product’s U-value is not NFRC-certified then you have to use a default value and, if you do that, you’re penalized,” adds Nana.

And as far as keeping the insects out of the house and still enjoying the outdoors, screen systems are available to work with the walls. Nana says that offering a screen system has opened up opportunities for business his company would not have known otherwise.

Competitive Products
If operable walls are the next big thing, does that mean the systems are taking market share away from the traditional patio door companies?

“It hasn’t to my knowledge,” says Wayne Gorell, chief executive officer of Gorell Windows and Doors in Indiana, Pa. “They are very expensive systems [and if there are maintenance issues] you have to be able to afford that labor.”

Christopher Burk, a product manager with Simonton Windows in Parkersburg, W.Va., agrees.

“It does not appear to be affecting [the patio door market],” Burk says. “Looking at percentages, and considering the door and window industry as a whole is down right now, we’re about the same as we were last year.” Burk adds that the operable walls are not likely to affect the replacement market much either because it would require major renovations.

One possible reason that patio door manufacturers have not been affected by the growth of operable walls is the fact that the wall systems are primarily used in high-end homes. Still, like most every other trend, these wall systems will work their way into the mainstream eventually. As they begin to penetrate that market segment, patio door companies will have to find ways to remain cutting-edge. Gorell and Burk have similar ideas for doing so.

“We can do whole walls of patio doors that open one panel at a time,” says Gorell. Burk describes a system with four to five track doors with every one being operable but the last one. These options can still allow homeowners an indoor-outdoor experience, without the heavy price tag. 

What’s Next?
The emergence of operable wall systems into the mainstream isn’t that far off. In fact, Nana says his company is already starting to see it. “It’s being offered by some developers as an upgrade. We won’t see it in track homes, but it does give some developers an advantage.”

Header says he, too, expects the products to eventually work their way into more homes.

“Our goal is to do that by improving manufacturing … in order to drive the costs down,” he says.

There are other areas that will pose challenges as the systems continue to evolve. Manufacturers say to expect energy requirements to become more stringent. They also expect to see a desire for bigger glass, and windload requirements can also make it difficult to use extra large pieces.

Today glass is a hot item thanks to the indoor-outdoor connection it can provide. If this trend continues it’s likely that so, too, will the popularity of opening, moveable walls. 

Ellen Giard is a contributing editor for DWM.



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