Feature Article - July/August 2004
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Top It Off

Enclosing a pool can increase program offerings and help draw new crowds

By Margaret Ahrweiler

Let the sun shine in

Glass enclosure systems also can bridge the gap between users who want an outdoor feel and those who prefer the great indoors.

"When we initially proposed this to our membership, there were a lot of cries that we want open air," Webster recalls. '"Now, the biggest complaint is that it's not closed enough."

Even when closed, the clear roofs allow swimmers and loungers the benefits of natural light without the hazards of exposure to ultraviolet rays.

The dramatic appearance of an enclosed pool can instantly increase visibility as well, aiding in marketing efforts.

"Before we installed the enclosure, our pool was hidden—people never knew we had a pool," Webster says. "Now, it's a focal point. People can walk up to our facility and imagine themselves from our pool."

By increasing the availability of the pool, enclosures can also help make popular programs more accessible. The Almaden Valley Athletic Club in San Jose, Calif., had to compress a year's worth of aquatics lessons into the summer months, with popular programs booked months in advance. But when the club enclosed its outdoor pool with a greenhouse-type system, its swimming program sprouted fins. Ten bays of sliding doors and 16 roof panels open up to create an outdoor feel while providing just enough protection from the vagaries of the San Francisco Bay weather.

"It's had a huge impact on their programming," says Rob Christie, president of the enclosure-system manufacturer that installed the club's system.

While exposure to natural light may not rank high on a California facility's list of priorities, the large expanses of glass can give a huge psychological and emotional lift to cold-weather facilities. For example, Meus is working on an addition with an enclosed glass leisure pool area at The Works, a fitness club in Somersworth, N.H., which is keeping its outdoor pool intact and starting from scratch with an indoor system.

"To be able to feel that sun in the middle of winter, especially if you have small children, is a big boost," Meus says. "It also allows you to use the pool on a rainy day, where you can close the roof but keep the doors open."

The glass enclosure systems feature three key points that make them different from stick-built systems: First, they're built of powder-coated aluminum, which is one of the few construction materials that does not break down when exposed to chlorine or moisture. By building the framing systems off-site to a pool's measurements, the construction team need not cut any beams, which weakens the corrosion resistance. (Cut spots expose uncoated metal, giving that corrosive chlorine an entry point.) These aluminum systems also feature a thermally broken design, which means that the inside parts are separated from the outside parts by rubber gaskets. This limits conductivity and helps reduce the condensation caused by big differences in indoor and outdoor temperatures. It also helps the structures adapt to a wide range of climates, from a Canadian winter to an Arizona summer, Christie says.

Next, they feature retractable roofs that can expose up to 40 percent of the facility to open sky and create an inexpensive, easy way to help regulate air quality. If it gets too humid or hot, you can open the roof. Some roof systems are composed of panels, allowing the option of only opening a few panels. Others feature sliding retraction systems, so that a roof can be "cracked," like a window or fully opened, exposing most of the pool. At the Mission Valley YMCA, the roof opens enough to expose four of the pool's six lanes.

And those roof panels do more than just let in light and air. The roof panels are made of polycarbonate, a tough yet clear resin-based plastic—think of a Nalgene bottle for your roof. Not only is polycarbonate much more durable than glass, it also protects against UV rays, allowing sun worshippers to get their fill without damaging their skin, Christie says. Finally, sunlight helps break down chlorine as well. Polycarbonate's high thermal resistance means it conserves heat (or in the case of hot desert climates, cool) better than insulated glass. The side panels of pool enclosure systems are typically composed of glass, laid between aluminum support beams, with banks of sliding doors—either patio style or the vertical "garage-door" variety that can open to create more of an outdoor pavilion feel. Some systems can incorporate columns of conventional walls with up to an R-20 value of insulation, Christie says.

With improved technology and engineering, prefab aluminum and glass systems can accommodate ever-larger structures. An enclosure system at the Milford/Orange YMCA in Milford, Conn., features a 100-foot wide span and rises to a height of 20 feet to match the existing building, Christie says. The systems will work with almost any pool, adds Dodson—the only thing prohibiting a structure might be a tight site, where the contractor could not squeeze in the foundation footings between a pool and an existing building.