Undercover Operations

With proper planning, adding a pool enclosure can boost patronage and profits

By Dawn Klingensmith

From the brisk Eastern Seaboard to the sunny coast of Southern California, aquatics programs are going under cover. It hardly takes detective work to figure out why. Covered pools keep out leaves and other pesky debris, not to mention midnight skinny dippers. They shut out chilly temperatures, thereby extending daily water time, lengthening the swim season and boosting patronage. At the same time, they trap in solar energy and keep chlorine from dissipating.

For all those considerations, though, consumer demand is the main thing driving the trend toward enclosed pools. Many Baby Boomers and seniors, for example, have come to rely on aquatic exercise for a low-impact workout. Needless to say, shivery pool water and chilly outdoor air offer no succor to sore joints.

Kids, too, are quick to complain about the cold.

"At both ends of the age spectrum, you've got swimmers who are more comfortable inside than outside," says Randy Mendioroz, whose firm, Aquatic Design Group in Carlsbad, Calif., completes 60 to 80 projects a year, some 10 percent of which involve enclosures.

For these and other reasons, pool enclosures have started showing up on the wish lists of many sports and recreation facilities. And while motives for going under cover are no mystery, figuring out which type of enclosure to buy—and whether your market even will support it—requires some sleuthing.

Under pressure

Several types of enclosures are offered at a variety of price points. At the most affordable end of the spectrum are vinyl-coated polyester air-supported structures, commonly called domes or bubbles, which generally are put in service for winter only and stored during the warmer months. Fans inflate the structures; once in place, continuous fan operation and positive inside air pressure are required to keep them inflated. Cables attach to beams around an air dome's perimeter to anchor it. Some models have see-through sides or screened windows. To maintain air pressure, revolving doors typically are used.

The insulation values of the air dome must be sufficient to prevent condensation at the lowest expected ambient temperatures, which generally is achieved in part by using an outer membrane in conjunction with a liner. Like a ski jacket, this two-ply fabric provides air spaces that increase insulation.

In certain climates, air-supported structures cry out for mechanical heating, ventilation and cooling (HVAC) systems to combat condensation and humidity. According to one manufacturer, most of the big players in the air-supported structure industry ship the dome, the inflation system, and a heating and ventilation system "all in one box." If you need to purchase an HVAC system as an extra, though, be advised that it probably may cost more than the air dome itself, and the associated operational costs will administer repeated bottom-line bruisings.

Critics of these types of enclosures say that proper ventilation is complicated by the fact that positive air pressure is needed to keep them inflated, so air quality and comfort become issues. Mendioroz has heard complaints that air domes make for swampy, stifling environments.

Another common complaint is that air domes don't "pop up" as easily as buyers might envision. When you consider that relearning how to erect your four-man tent when camping every year can be a lesson in humility, you'll start to understand why. Most air domes take at least a day to inflate and two or more days to collapse and put away. To extend the tent comparison, if you've ever stuffed your tent in its bag after a rainy camping trip without drying it out first, you'll recall the unpleasant olfactory surprise that awaited you when you next unpacked it. So, to prevent mildew and increase the odds that an air dome actually will live out its purported 10-year life expectancy, you need to make sure it's thoroughly dry before folding and stowing.

In summary, air-supported structures should perhaps be thought of as affordable short-term solutions for pools simply aiming to stay open through the winter but may not be an ideal option for aquatics facilities looking to develop robust, year-round programming.

Right on tracks

Also at the less expensive end of the spectrum, telescopic enclosures cost more than air-supported structures but offer increased versatility. These structures usually consist of polycarbonate—or some other type of glazing—and extruded aluminum arches, each of which nests inside a slightly larger one so that the structure opens and closes like a telescope.

The system operates either by way of deck-mounted tracks, which function like sliding-door closets, or via trackless rollers. Taking safety and convenience into account, the track design probably is more suitable for nonresidential applications, as the tracks anchor the structure. Trackless models must be fastened to the ground section by section when wind is expected.

Most U.S. manufacturers of telescopic structures tend to target residential pool owners. According to one manufacture, the industry is still in its infancy, and the technology hasn't advanced to the point where large-scale commercial applications are feasible. Therefore, relatively few nonresidential pools rely on telescopic structures for respite from bad weather, but it's an industry that is worth keeping an eye on, perhaps.

Rock solid

At the opposite end of the spectrum in terms of cost and permanence are brick-and-mortar types of enclosures. The low-slung, windowless design that seems to have served as the template for natatoriums of a certain age are not at all what communities have in mind these days when they set out to build an indoor pool. Instead, they envision the pool as the crown jewel—an aquamarine gem, if you will—in a welcoming multipurpose recreation facility that meets a community's sundry needs and desires. While indoor waterparks are exploding in popularity, across the board, facilities hear louder demands for warm-water therapeutic pools as the general population ages, Mendioroz says. These demands are sparking a trend. As recently as a few years ago, when sports, parks and recreation professionals would float the idea of building a therapeutic pool, such projects often stalled..

"The response was 'Oh, wouldn't that be nice,' but the nothing was ever done," he says.These days, there's a bandwagon tendency toward paying more than just lip service to providing therapeutic pools for patrons' use—even within recreation departments that already have a 50-meter pool outside, he adds. Why?

"Communities are insisting on it," Mendioroz says. Hence his firm has been fielding inquiries about indoor pools, specifically of the brick-and-mortar variety. But, there is a catch.

"When you tell people what it's going to cost, there's a huge intake of breath," he says with a laugh.

The average cost for conventional construction is $300 to $400 per square foot. Put another way, an outdoor 50-meter pool typically ranges from $3 million to $5 million, but if you build brick walls around it and crown it with a roof, that same pool will cost $8 million to $12 million, or more than double the price, Mendioroz says.

"[A pool environment presents] the worst possible conditions with the exception of a meth lab in terms of chemical nastiness," he says, and on top of corrosive chemicals you're dealing with humidity, another archenemy of conventional construction materials.

Concrete and steel stand up to these nemeses tolerably but not without armor. Steel trusses must be fabricated with their inhospitable environment in mind and coated with specialty paints to guard against corrosion. Masonry needs a vapor barrier. All vendors involved in the project need to know that their materials are bound for a pool environment.

Long-span roof trusses must be used.

"Because you obviously can't have support columns in the middle of your pool or deck," Mendioroz says. Installation of such trusses calls for stepped-up safety and handling measures, which affect labor costs.

To top it all off, heating a fully enclosed building that's large enough to house a pool can be extremely expensive, he adds, yet absolutely necessary since the air temperature must be kept two degrees higher than water temperature to keep condensation from forming on walls and to assure guests' comfort as they emerge from the pool.

The breathtaking expense of building and maintaining a fully enclosed brick-and-mortar pool keeps facility planners open to other options.

"People are looking for alternatives," Mendioroz says.

One notable result is that commercial swim schools are cropping up in retail environments. According to Sue Davis, a San Jose, Calif., swim school director (who is not necessarily a fan of the phenomenon), some California schools are retrofitting pools into existing buildings.

"So, for example, they'll move into a strip mall and put a pool in what used to be a grocery store," she says.

Know the Code

Prefabricated see-through pool enclosures can be assembled in a matter of days, and when the last panel is in place, occupants ideally don't sense the presence of the structure and feel seamlessly connected to the great outdoors. But make no mistake: These are permanent structures, and just like their brick-and-mortar brethren, they are subject to strict building codes.

The Lompoc Aquatic Center in Lompoc, Calif., is one of the largest enclosures of this type ever built, and in part because of its size, architect Jim Moore had to clear three daunting California Building Code (CBC) hurdles.

  • Per CBC Chapter 31 B, occupant load calculations are based on a ratio involving the surface area of the pool. Using this method, Moore arrived at 775 occupants, a number that normally would require an A2.1 assembly area occupancy classification, which entails fire rating the structural frame. The manufacturer's aluminum frame system did not lend itself to this type of treatment. Using an exception spelled out in CBC code (1003.2.2.2), Moore prepared and gained approval of an occupant load management plan and added exit doors to his design. By doing so, he attained an A-3 occupancy classification for the enclosure, which does not require a fire-rated structural frame.
  • The enclosure's double-layer polycarbonate roof panels have a Class C fire safety rating, but based on occupancy class, a Class B roof rating is required. Satisfying this requirement meant limiting the use of polycarbonate to no more than 33 percent of the roof area. Working with Moore, the manufacturer designed a three-component roof system, using the standard polycarbonate for the operable roof sections, which took up the allowable 33 percent, and fixed insulated glass and metal panels in all other areas. All materials were specified in a blue color to maintain the aesthetic harmony of the roof.
  • Due to the large size of the enclosure, CBC Section 505.3 required that a full sprinkler system be installed. However, the building department ultimately ruled that areas directly below the operable roof did not need sprinklers because the retractable portions of the roof are situated directly over pool areas. Moreover, installing sprinkler heads in the operable roof area belied common sense because whenever the roof was open they would lack the heat bank necessary to activate them in case of a fire.

Pleasant under glass

If putting a pool in an old Piggly Wiggly lacks appeal and conventional construction is out of your price range, prefabricated see-through enclosures with retractable roofs can be an attractive option that not only offers permanence but also the added bonus of an outdoorsy feel.

"Basically, they look like greenhouses," Mendioroz says, adding that their cost, at $100 to $150 per square foot for a top-quality system, is less likely to elicit a cry for smelling salts.

Designed specifically to withstand harsh pool conditions, these systems are composed of a corrosion-resistant extruded aluminum frame, roof panels made of clear or tinted polycarbonate, and glass wall panels. The glazed components come with UV filters to block out harmful ultraviolet rays.

"They ship you all the parts, and you assemble it on site, like a big Erector Set," Mendioroz says. "It's kind of cool."

These systems also feature a thermal break design, which means inside parts are separated from outside parts by a low-conductive material that reduces the transfer of cold and heat, thereby preventing condensation caused by an indoor-outdoor temperature difference. Due in part to this feature, prefabricated pool enclosures are suitable for all types of climates, from sunny Los Angeles to snowy Alaska, although the venting requirements will differ from one climate to another.

Several configurations and roof types are available, including gable, hip, shed and offset ridge. Walls can be solid or made of glass with banks of sliding doors.

On blue-sky days, the roof and walls can be opened to create an outdoor pool environment, complete with direct sunlight and warm summer breezes. In cold or inclement weather, the roof and walls can be closed up tight with no threat of inducing cabin fever.

When the Almaden Valley Athletic Club Swim School in San Jose, Calif., opted to enclose its instruction pool six years ago so it could offer lessons year-round, the promise of a retractable roof is what got Davis, the program's director, on board. It was as clear to her as anyone that offering lessons year-round would be preferable to the seasonal program AVAC had kept in place for nearly 40 years.

"It was frustrating to make progress with kids over three or four months and then have to stop in September," she says. For the next seven months, the kids would have no access to a pool.

"So when they'd come back the next summer, instead of building on the skills they learned, you'd have to start all over again," she adds.

However, Davis—who grew up swimming competitively and spent countless hours at indoor pools where the reek of chlorine was like an assault—was somewhat wary of the proposed construction.

"I was concerned about dank; I was concerned about smelly; I was concerned about that awful closed-in feeling," she says, until a striking glass enclosure with an operable roof was settled upon.

Program Expansion

Offering a combination of core and creative programming will pack your pool and increase profits. Some ideas to consider:

  • Infant water-orientation classes and learn-to-swim programs for all ages
  • High-school and age-group swim meets
  • Water walking, water running, water kickboxing and other forms of aqua aerobic and strength-building workouts
  • Prenatal and post-natal mom and tot aqua fitness classes
  • Water yoga
  • Senior fitness days (offer blood-pressure testing and other health screenings free to the public and invite seniors to participate in a water fitness class)
  • Springboard diving lessons
  • Lap swimming
  • Scuba-diving lessons (for pools with at least 7 feet of water)
  • Basic kayaking skills classes
  • Physical and water therapy
  • Birthday parties and "dive-in" movie parties (guests watch family-friendly films from the flotation device of their choice)
  • Water polo matches
  • Synchronized swimming
  • Water relaxation floats
  • Triathlon training
  • Special Olympics

Breathe easy

Air quality was also a concern for the parks and recreation department of Lompoc, Calif., when it set out to put three pools under one humongous roof. Currently under construction with completion expected in time for summer use, the aquatic center replaces the old Lompoc Municipal Pool, an indoor facility that was condemned in 2000 for its failure to meet earthquake safety standards. The old pool had been open for business 14 to 16 hours a day, seven days a week, yet for all its bustle of activity, it was far from perfect.

"It was like having a toolbox with only one tool in it, so you try figure out how to use that tool for a variety of tasks, without much success," says Dan McCaffrey, Lompoc's director of parks, recreation and urban forestry.

In other words, the city's pool was not meeting the needs of all its constituents. Hence Lompoc officials had the community's support to build a $13.2 million, 41,000-square-foot aquatic center with three separate pools—a 10-lane competition pool for swim meets and water polo matches; a therapy pool with 90-degree water and a wheelchair ramp; and a recreation pool with toddler-friendly zero-depth entry and splash play features on one bean-shaped end as well as four lanes for lap swimming, water fitness classes or recreational use in the rectangular middle and a two-flume water slide complex on the other end. The cost of the sprawling facility would have been much steeper were it not for the prefabricated enclosure covering the 31,000-square-foot pool area, says project architect Jim Moore of Phillips Metsch Sweeney Moore Architects in Santa Barbara, Calif. A 10,000-square-foot brick building houses the lobby, locker rooms, offices and mechanical room. Relative to the entire cost of the project, the enclosure was a bargain at $1.8 million.

Moore believes the enclosure will be perhaps the largest of its type ever erected. And while the sheer size is a point of pride, it also presents a challenge in terms of venting.

In California, pools with retractable-roof enclosures don't necessarily need HVAC systems. If it gets too hot or humid inside, you can open the roof. Because the roof is composed of panels, the system allows for flexibility.

"You can open all of them or just one of them," Mendioroz points out. "You can open some of the panels all the way, or all of the panels part of the way, or you can crack a panel like you would a car window."

Opening a combination of wall and roof panels creates a "natural flue effect, so ventilation doesn't cost a lot of money," he adds.

Given the enormousness of the Lompoc pool enclosure, the manufacturer developed a control plan whereby employees will vent particular panels in specified ways if rain threatens to cause indoor fogging, for example, or if it gets too hot and a cross breeze is needed. In the event that this control plan proves to be insufficient, in his design Moore included infrastructure for a dehumidification system so one can be retrofitted. By not including a dehumidification system to begin with, the city saved $750,000. However, not every climate is so lucky.

"In someplace like Denver or Reno where you get snow, you probably couldn't get away with not having a dehumidification system," Moore says.

Building to code

An important factor to keep in mind if you're in the market for a prefabricated enclosure is that these systems are considered permanent structures and are subject to building codes that you'll need to be aware of in advance.

"What I recommend is that architects meet with building officials beforehand so there aren't any surprises," says Mendioroz, referring to unplanned obstacles that tend to stretch timelines and stress budgets.

The Magdalena Ecke Family YMCA in Encinitas, Calif., learned this lesson the hard way when it tore up its small, two-lane lap pool and diving well, which "weren't getting the job done" for the club's 20,000 members, says Aquatics Director Chris Wallick. In their place, the YMCA built a 25-yard-by-25-meter pool to be used for lap swimming, swim meets and water polo as well as a separate warm-water pool designed with the needs and comfort of seniors, children and recreational splish-splashers in mind. Both pools will be covered with a prefabricated enclosure.

The YMCA planned to erect the enclosure in two phases so that one of the pools would remain open throughout construction, however, in January the club made the decision to close both pools after encountering an unexpected snag. Late in the process, the YMCA found out that municipal building codes mandated the installation of a sprinkler system.

"Just in case the water, the aluminum or the concrete catches on fire," Wallick says with an incredulous laugh.

Already behind schedule, the YMCA closed both pools to expedite its ability to bring in the necessary equipment and contractors needed to satisfy all the requirements for the permits.

The completed project will be worth the wait, Wallick says and expects it will pay off in the end.

"[The $1 million roof] plays a vital role in our ability to run programs year-round and at a high level day to day," he explains, adding that the club can now offer more swim lessons, water fitness classes, and designated lap or family swim times. The club also has plans to rent the pool to the local high school for water polo and to physical-therapy providers.

At its apex, the enclosure soars 30 feet above the water.

"So you won't feel like you're being sat on so to speak by the roof," Wallick says. More than 60 percent of the roof can be retracted to appease sunbathers. The roof is blue on the outside and white on the underside, so when the sun strikes the closed panels, there's a light-blue glow inside, he says.

Enclosure Vocabulary

Clerestory A row of windows near the top of the wall. A clerestory can be incorporated into the design of a natatorium or prefabricated enclosure to bring daylight into the pool area.

daylighting An architectural buzzword for using natural sunlight to illuminate a building's interior through strategic placement of windows

extruded aluminum One of the few construction materials that can withstand prolonged exposure to chlorine and moisture. Retractable-roof and telescopic enclosures usually have extruded aluminum frames.

glazing Glass or polycarbonate panels set into frames. Prefabricated enclosures usually consist of glazing and extruded aluminum components.

no drop A coating sometimes applied to roof panels to prevent condensation and cause rainwater to form a film and flow off evenly

polycarbonate Durable resin-based plastic used as a shatterproof substitute for glass in retractable-roof enclosures

r-value A measure of the capacity of a building material to impede heat flow, with increasing values indicating greater capacity. The color of polycarbonate panels in prefabricated structures will affect their R-values.

rainscreen principal A design approach for restricting rain penetration into the building components of an enclosure through use of gaskets, baffles, overlaps and seals that prevent seepage while allowing for pressure equalization. Air seals bar contact between interior humid air and cold surfaces or structural components to prevent condensation and ice buildup in cold weather.

tension structure A type of structure that uses compression, tension, and fabric and cables for structural stability. Tension structures can be used to enclose pools, however, unlike air-supported structures, these are considered permanent.

thermal break Design in which high-conductive materials are separated by a low-conductive material to reduces the transfer of cold and heat. In pool-enclosure roof panels, this type of design helps prevent condensation caused by an indoor-outdoor temperature difference.

Let there be light

A variety of other roof colors—including bronze, opal and clear—are available. Panel colors affect insulation values. Mendioroz recommends translucent panels for the lower walls, although it's safe to incorporate some transparent panels in a north-

facing wall for a nice outdoorsy feel. Be careful elsewhere, though.

"You don't want to create an unsafe situation where your lifeguard can't see the water because of the glare," he says. If you've opted for floor-to-ceiling glass walls, shade the lower walls and do a transparent clerestory, so the unshaded windows are 8 to 10 feet high. That way, when the sun is low on the horizon, you'll get a nice, diffuse light.

"Sunlight usually isn't a problem if it's coming in high," Mendioroz says, adding that daylighting—an architectural industry buzzword for bringing natural light into a space—helps reduce energy costs.

Due to budget constraints, the Magdalena YMCA's new aquatic center has solid 10-foot walls on all four sides with three feet or so of glass glazing on top before the walls meet the slope of the roof.

"We're on a little hill overlooking the Pacific Ocean, so it would have been nice having glass walls all the way around," Wallick says, but his budget wouldn't allow it.

In fact, in the planning stages of the project, Wallick had to push hard to get an enclosure at all. When faced with an enormous price tag for the aquatic center upgrade, plans for the enclosure we're on the chopping block to lower costs.

"The roof stuck out at people as the obvious thing we could cut," he says.

Wallick got his way, but before the enclosure went up, it already was becoming apparent to people why he'd been right about its indispensability. While the new pools were uncovered, participation levels dropped precipitously when winter rolled around.

"One of the reasons for enclosing the facility is that we have a healthy senior population here, and they're very active," Wallick says. Thrice-weekly water fitness classes for seniors were drawing a group of 60 regulars, however, attendance dwindled to five to seven people in the winter.

"This is a class they absolutely love," Wallick says, "but the weather was a huge deterrent for them."

Moreover, staff morale plunged along with the mercury.

"It's miserable sitting in a lifeguard chair when it's 50 degrees out," he adds.

Davis of the Almaden Valley Athletic Club Swim School says weather can be a morale-sinker even in the summer in Northern California.

"When evening rolls around, and the sun's not hitting the water, it gets cold," she says. "The teachers shiver; the students shiver. That's not a conducive learning environment."

After AVAC invested in an enclosure, swim school participation grew from 1,600 students per week when it was a summer-only program to 4,500 per week. Enrollment drops off in winter, but with 3,400 students showing up each week, the school is seeing 100 percent more business even in the slow season. AVAC is on target to gross more than $3 million this year, up from $500,000 in its final year as a seasonal outdoor facility.

Pumped-up programming

Having an enclosed pool enables you to develop year-round programming and to make use of early morning and evening hours, when lower temperatures usually would discourage folks from taking a dip. To ensure a return on investment, packing your pool is essential, and in order to do so you'll need to come up with creative and diverse program offerings.

Before getting creative, though, it's essential to get the basics down first, says Ted Boyett, award-winning aquatics director of the University of Rhode Island's Tootell Aquatic Center. With extended hours of operation come increased maintenance and staffing demands, so you'll want to get a handle on these before you start cramming your aquatics programming with fancy fare like water ballet and synchronized swimming. Understand, too, that unless you have a greenhouse type of enclosure, temperature adjustments might be in order.

"Indoor pools tend to feel colder than outdoor pools because the sun's not warming the water," Boyett says.

Work on developing solid core programming before moving on to more creative offerings. Core programming will differ according to clientele, but if you're aiming to appease the general public—while at the same time turning a decent profit—focus on your learn-to-swim program, which will be the key revenue producer, Boyett says. Water fitness classes rank second in terms of revenues; together, these two offerings will anchor your aquatics program, he adds.

Having age-group and other swim teams practice and compete in your facility isn't as lucrative as learn-to-swim classes, however, competitions draw public and media attention, which is good for business, Boyett says. Masters swim programs aren't especially lucrative either, but master swimmers "make great lobbyists for your pool," he adds.

Considering that your staff needs various certifications anyway, it makes sense to open these certification opportunities—CPR classes, for example—to the public for a fee.

The key to robust, successful aquatics programming is "running a three-ring circus," Boyett says. Space permitting, you'll want to have more than one program going at any given time, so long as they don't interfere with one another. At the Tootell Aquatic Center, which has a four-lane warm-water pool, a diving well and an eight-lane competition pool, Boyett sometimes has as many as seven or eight programs going on at once.

Likewise, the Lompoc Aquatic Center's three separate pools will enable the parks department to slip into the role of ringmaster fairly easily. The 10-lane competition pool, surrounded by a cantilevered deck, will be kept at a temperature that's safe and comfortable for aggressive swimmers, McCaffrey says. A 1,600-square-foot therapeutic pool, which features a wheelchair ramp and a portable lift to provide access to it and the other pools, will be kept at 90 degrees. The third and largest pool has dedicated space for family fun. A splash playground at one end features two small water slides, a 300-gallon tipping bucket, umbrella jet sprays, interactive arching jets, pull ropes and other in-pool playthings. At the opposite end are two larger water slides—one open and one closed, like a tube—rising 18 feet above the water and traveling about 100 linear feet down to a 23-foot-by-25-foot section of the pool.

The local high-school swim team, as well as club, master and Special Olympics teams, will use the competition pool. So too will lap swimmers and water polo leagues. Basic kayaking skills will be taught there, and the parks department also has plans to use the pool for the swimming portion of mini-triathlons.

Running a three-ring circus serves dual purposes. First, it allows you to meet the needs of your diverse clientele. Second, it exposes devotees of one type of program to some of the other programs that are available, which can boost participation and profits.

When you're developing programming to pack your pool, it pays to keep two more things in mind, Boyett says. The first is a trend toward half-hour or 45-minute express workouts as opposed to hour-long water-fitness classes. Condensed classes make it easier for folks to squeeze in a workout in the morning before business hours or during their lunch break. At the same time, briefer workouts enable aquatic directors to squeeze more classes or programs—and more paying customers—into each day.

The second thing to keep in mind when return on investment is a priority is the comfort of your swimmers.

"Warmer water sells," Boyett says. You'll draw more participants and build a more satisfied customer base when your pool feels less like an arctic plunge and more like the sun-warmed Pacific.

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