A Plan Four All Seasons

Four-season design for recreational enclosures

By Kelli Anderson

When the Woodruff Family YMCA in Milford, N.J., reopened the pool in May 2005 with an enclosure of polycarbonate panel and aluminum, they prepared for an increase in membership. "We were at approximately 4,000 members and had a target to 6,000 in two years," said Phil Dwyer, president and CEO of the Central Connecticut Coast YMCA in New Haven, Conn. "But by year end of 2005—what is that, seven months?—we were at 7,000. The reaction of the community was instant success. It blew well past our expected goals."

The YMCA's local leaders knew the facility needed both an outdoor and indoor pool experience for its patrons and began to provide that over a decade earlier with a bubble structure erected during colder months and dismantled during the warmer ones. Although this was a good first step toward fulfilling patrons' wishes and building revenue, it wasn't a permanent solution. After the second bubble of 11 years collapsed, and frustrated with the rising heating costs thanks to oil-price increases, they were ready for something new.

But what to choose? In today's market, four-season designs come with several material options, and selecting the right one depends on factors such as programming, geographical location, budget and aesthetics. Whether the structure is air-supported, panel- or fabric-and-frame, to name the most common, all share the basic qualities desired by patrons everywhere—natural light.

Let there be light

"Cheerful," "bright" and "open" are all terms people typically associate with a naturally lit environment. Studies repeatedly have shown that natural light makes us feel better and perform better in almost every venue. Add to that the fact that light-transmitting structures can, depending on their makeup, block harmful UV rays, use the greenhouse effect to reduce heating costs and greatly reduce the need for lighting utility costs, and it's easy to see why they're such a smart option.

When Jim DiBellonia, managing partner of the Waves Indoor Water Park in Niagara Falls, Ontario, was doing his research on enclosed waterparks in the United States, he was surprised to find that none he investigated took advantage of the light-transmitting structural options. "For an indoor waterpark it was the best decision for lighting. It was nice, bright, good—none of that gloomy, woodsy feeling," DiBellonia said. "People just weren't thinking outside the box."

DiBellonia raved about the passive solar gain that has had a tremendous impact on reducing heating costs in colder months. And the facility's 64 1,000-watt fixtures are not used at all in summer, and are used minimally even during the shorter days of winter, which makes a big difference on the waterpark's electric bill.

"We needed a building to offer guests the environment they were looking for," DiBellonia explained, "and for one that meets or exceeds our energy codes." The building they got was a mix of materials to achieve all of these needs: insulated aluminum panels, glass and polycarbonate.

And natural light isn't an advantage only for panel-and-frame structures, but for air- and frame-supported fabric structures, as well.

Generations Sports Complex's Second to None (STN) Sports Dome in Williamsport, Pa., now boasts the largest air-supported structure in the United States. The dome, which is approximately two football fields in length and one in width, hosts a wide variety of activities. "We don't have to turn the lights on until it's pitch-dark outside," said Rob Eaton, director and owner of Second to None Soccer.

"It's helped with utilities, and the atmosphere is tremendous."

Notes from the School of Hard Knocks

When it comes to any new project, nobody wants to reinvent the wheel or have to earn a Ph.D. from the school of hard knocks. This list contains a few dos and don'ts from those who've already been there, done that with their four-season structures.

  • Have more than one air-handling system for a backup or else two smaller systems.
  • Put a colorful "sock" over the handling system to set off a space that is usually boxy and unsightly.
  • Research the handling system as part of your structural selection process— it's all part of the package and essential to overall success.
  • Heaters often corrode; try a drop-aluminum heater with temperature gauge.
  • Make sure conduit in wiring for the structure is not galvanized to avoid corrosion.
  • Get a backup generator for peace of mind to offset the deflating effects of a power outage.
  • Build a foundation (2 to 3 feet high) on which to place the structure so the base will not be damaged by snow-removal equipment.
  • When transparent or translucent paneling is near the ground, it is a good idea to landscape as close to the base of the building as possible to prevent splash-back of unsightly dirt during rainy weather.
  • Meet with as many suppliers in person as possible.
  • Visit other facilities and ask what they recommend per their experience.
  • Pay attention to a company's overall attention to detail and "willing" attitude in the event that their cooperation is needed for an unexpected problem.
  • Compare warranties.
  • Bring all players to the table early in the process.
  • Make sure the company is familiar with the local energy codes.

Cost-effective building solutions

Another reason for the STN Sports Dome's air-supported structural choice was even more compelling—economics. "We wanted an economical and large space," Eaton explained. "What we got was more economical than steel."

In general, four-season structures are a cheaper building alternative to traditional construction, with the added advantage that they can be built faster.

The most cutting-edge material—not yet utilized in the United States but already stunning ski resort and spa patrons in Germany—is ETFE-foil (ethylene tetrafluoroethylene). The façade of the state-of-the-art Allianz Arena football stadium in Munich, Germany, is constructed of nearly 2,900 ETFE-foil inflated air panels. The panels can be individually lit with white, red or blue light, a tool the stadium employs to distinguish who's playing.

Although initially expensive, the material is so lightweight that a little goes a long way, translating to lower per-square-footage costs than conventional construction. Add to that its almost magical transparency and impressive R-factor (or thermal resistance factor), and you've got another four-season construction contender on the U.S. horizon with a first-ever project planned for this year in Iowa. (For more information, visit the Lightweight Structures Association Web site at www.lightweightstructures-ifai.com.)

Energy efficiency

One of the biggest building design trends around the world is "green"—which coincidentally, is both good for the environment with its emphasis on energy efficiency and good for the pocketbook. Four-season designs are perfect for both.

"One big change is that energy codes are much more conservative than five years ago," said Mike Crowder, a national sales manager with a panel-and-frame company. "The latest round of oil-price increases coupled with the green movement has designers looking to more energy-efficient solutions."

In most panel-and-frame or fabric structures, energy efficiency starts with an ability to take advantage of solar heat, while some materials boast additional insulation properties. Some fabric designs, for example, can be double-layered to allow trapped air to act as an insulator, while some companies combine different panel materials to achieve the desired effect between light and insulation. Some proprietary panel

materials possess both translucence and an impressive R-factor.

Conversely, cooling costs are also reduced by many of the designs found in four-season construction. In aquatic facilities, panel-opening features, both automated and manual, allow fresh outdoor air to do the job of air-handling systems by naturally cooling and dehumidifying the indoor space while releasing corrosive chloramines.

Open-panel systems also give patrons the two-for-the-price-of-one experience of feeling more connected to the great outdoors while actually gaining the benefits of an enclosed space. In many cases, large side doors as well as ceilings open for maximum effect. Depending on the manufacturer, panels can be opened either as a group or individually.

In the design of the Waves Water Park, the benefit of patrons being able to experience fresh air while the facility simultaneously reduces its energy costs was a no-brainer decision for the owners. "The operable roof is fantastic for spring, summer and fall for the HVAC," explained DiBellonia, whose emphasis on 100-percent makeup error for the waterpark's air quality is non-negotiable. "We don't recycle any air. Four times an hour air is pumped out and fresh air dumped in."

But fresh air isn't only for the panel-and-frame designs. Fabric designs, too, can provide fresh-air comfort while cooling down energy costs. "Our frame-supported-fabric building is translucent with solar heat and light coming through," said Steve Dansky, co-owner of Winning Touch Tennis of Lehigh Valley in Allentown, Pa. "During nice weather we open the ends of the building. People can play in the shade where 96 percent of harmful UV rays are blocked by the fabric, preventing sunburn and cancer."

But not all systems are created equal. In the case of the Woodruff Family YMCA, rising oil costs translated into higher wintertime costs of heating the old bubble structure, which literally blew money out along with its heated air. "We spent $50,000 on utilities initially for the bubble, and then it went up to $120,000," Dwyer said.

"We were heating the air and then pushing it right out."

Although the bubble had served its purpose well, the pressure of higher utility costs factored into the decision to change to a new type of structure.

Beautifully done

Changing for the better also includes greater adaptability to conventional looks and a variety of aesthetic choices for four-season designs. The days of the single-use covering over a lone pool or single tennis court are giving way to combining these structures into existing athletic facilities.

"I think there's a trend that these structures are becoming more integral with more complex projects," said Bruce Wright, editor of Fabric Architecture, a publication of the Lightweight Structures Association (LSA) of Roseville, Minn. "They're not all by themselves, but integrated with other building parts."

Although a greenhouse look still has a classic appeal, some manufacturers are capable of creating a conventional facade that blends into virtually any style or material including brick, stone, stucco or wood.

As technology improves, so does the versatility of these structures, which boast wide expanses of open interior space and dramatic exteriors of soaring, sparkling, almost free-form designs. From contemporary to classic, there is a style and material to suit every need.

"It's just a beautiful facility," said Lane Walberg, senior program director of the Downtown YMCA in Jackson, Miss., of their panel-and-frame pool enclosure. "And it's very low maintenance. I will also say this—we had strong winds from Hurricane Katrina, and it didn't blow panels off the roof. It held strong."

Going strong

Beauty and strength—not always synonymous—are a special feature of these often-fragile-looking structures. It is not uncommon to hear stories of conventional structures faring far worse than their fabric- or panel-and-frame-structure counterparts during hurricanes, high winds and tornados.

"When in '99 a tornado hit Oklahoma City," recounted Alan Dodson, president of a distribution company in Garland, Texas, "it destroyed every roof on the college campus except ours—the frames weren't affected at all."

For some manufacturers using aluminum rafters and columns, the amount of deflection—or how stiff a building is—has reached impressive heights (180 feet) allowing both larger spans of open interior space and greater strength to withstand movement while preventing thermal breaks between glazing.

Fabric structures also post some pretty impressive stats. "The advantage fabric has over other building materials is that it is more flexible and can withstand the elements," said Beth Hungiville, managing director of LSA. "There are strict regulations and guidelines to withstand winds of a certain amount. We pass them every time."

One reason fabric structures are so flexible, and what makes them as strong as and sometimes stronger than their traditional counterparts, involves the primary engineering use of tension in fabric structure design as opposed to compression in conventional construction.

However, despite the strength a structure may possess, some will require more monitoring than others when it comes to facing the elements. For some structures like air-supported fabric, constant monitoring of internal and external air pressure, and measuring wind and snow loads, is a must.

"Weather is a consideration," admitted Fred Marty, executive director for the Generation Sports Complex's STN Sports Dome. The structure can withstand winds of up to 70 miles per hour, but it's not as likely to make it through a tornado or hurricane. "Snow loading isn't as much of a problem because as heat rises it melts the snow, which slides right off. But the challenge is to consider handling all those factors."

Keeping up appearances

Even when exterior structures are up to the task, interior conditions can spell trouble. Most panel-and-frame structure manufacturers are savvy to the destructive potential of aquatic spaces and build their structures out of corrosion-resistant aluminum with the added aesthetic and protective benefit of paint or even powder-coating. But regardless of a structure's plus-points, aquatic spaces can still wreak havoc on both the interior and exterior materials if proper care is not taken to ensure that a good-quality air-handling system is in place—one suitable to the size of the space and conditions of the geographical area.

Case-in-point: One aquatic facility located in the South continues to battle high heat and humidity because opening the structure's panels to the equally high heat and humidity of the outside environment offers no relief. As a result, they find themselves battling interior fog, mold, uncomfortable temperatures and the constant corrosion of heating units. Although the structure is sound and met intended needs, an inadequate air-handling system without a proper dehumidifier to make the indoor climate comfortable has resulted in less-than-ideal conditions. A pool enclosure that normally would require no maintenance now requires bleach and a hand cloth to wipe down the constant encroachment of mold. It didn't have to be that way.

Stand by your plan

As with any building project, selecting the right players is key for a happy ending, with none being quite so important as the architect.

"The key player is absolutely the architect," said Pierre Lebel, a regional sales manager for a panel-and-frame company. "You want a facility to look nice, but it's never just a pool enclosure. You usually have a bathhouse that needs to match the architecture, or with clubhouses you have to try to fit it into a larger facility—to work the two systems in a way that meshes together."

All in all, it takes a lot of coordination and sufficient communication with various players.

"The architect should steer—they compile a team to talk to one another," Crowder said. "They should be dedicated to that market and conversant with HVAC manufacturers, engineers, et cetera. You really have to stress a meeting with all the players."

Stress communication. Often. And did we mention the need for communication?

"I had to make sure the engineers were in communication with the concrete contractors for proper footings and with the framers for north and south walls," recalled Jim Dickerson, owner of the Francis Scott Key Family Resort in Ocean City, Md. "They had to know what was going to be there."

But sometimes even the best-laid plan for your team selection needs a backup. "Always have a plan B," Dickerson advised. "I can tell you from experience with a contractor who died and we had to go to another one—I didn't have a plan B. I was lucky to get another contractor. Now we always get two or three quotes."

Getting the best players for your team can be a tricky business. Previous experience can make some selections easy, while other selections, normally a local choice, may require you to go farther afield to find someone with a history of specific experience—especially when it comes to locating mechanical systems for aquatic spaces.

Many times the enclosure manufacturer will provide suggested mechanical system suppliers to ensure that a knowledgeable approach to maintaining interior air quality is achieved. One-stop-shopping is a characteristic of some manufacturers, while others may simply make recommendations. However the players are assembled, making sure they communicate effectively so that the right hand knows what the left is doing will result in a good finished product.

Knowing what you want—and what you don't want—before going into a project certainly helps inform your ultimate decisions. "The big thing is to make sure you know what you want," said Rex Outhier, senior program manager of Great Plains Family YMCA in Weatherford, Okla. "We knew we wanted something more open with natural flow and natural light. Our board went to a lot of pools, and one of the biggest issues was circulation and rotting chlorine. Everything rots over time. We could have gone with electric panels, but we went manual and we went with powder-coated beams. It's worked really well."

Thanks to today's technology and advances in architectural design, recreational spaces housed in four-season structures wow us from the impressively large, such as the STN Sports Dome, to the über-fantastic Allianz Arena. Whether a small bubble, a stunning panel-and-frame or the breathtaking expanse of translucent fabric, there is a perfect solution to your year-round recreational needs.

Consider This

Qualities to look for when trying to decide what four-season structure is right for you vary greatly depending on climate, programming needs and the all-important budget. Here are the top five factors to consider before taking the plunge into the revenue-generating adventure of four-season design:


Smaller air-supported "bubbles" are a traditional first step in expanding a limited programming season to one that can operate year-round. These smaller structures are usually among the most affordable and can help increase revenues, which often leads to the creation of large, more permanent structures. ETFE-foil from the lightweight structure family or panel-and-frame structures, which tend to be on the higher end of the cost spectrum, are still cheaper than their brick-and-mortar counterparts.

Budget should also factor in long-term costs of material replacement over time, utility costs required to maintain the structure and necessary operating equipment. Utility costs for heating, cooling and lighting the structure are commonly offset by features particular to many four-season designs, including natural light and solar energy from transparent or translucent structural material and retractable roofs, doors or openings. In the case of aquatic spaces, the necessary mechanical systems needed to properly manage air quality need to be part of the enclosure purchase question.


The appeal of almost every four-season design is its ability to flood an interior space with natural light. Depending on the structure's material, insulation needs may have to sacrifice the amount of light or quality of light a structure can provide. Some fabrics need to be doubled to provide greater insulation, thereby allowing less light to filter through. Some panels with superior insulation quality let in good light, but are not transparent. Some panels are transparent, but do not insulate as well and will result in higher energy bills. And some materials let in the full spectrum of light, including dangerous UV rays.

Be sure to balance your energy-efficiency needs with the atmospheric quality you are looking for.


While almost all four-season designs are virtually maintenance-free, some do require more than others. Some panel-and-frame systems require occasional cleaning. Smaller bubble structures can take quite a bit of manpower and several days to assemble or dismantle the enclosure for the season. Air-supported structures—especially the larger ones—require additional personnel to run equipment needed to constantly monitor weather conditions and air-pressure regulation.


As more and more four-season structures are part of larger, complex facilities, consider the aesthetic flexibility of the structure and whether its look will add to, blend in or detract from the overall facility appearance.


Geographic zones with properties of cold/moist, hot/arid or hot/moist all require different elements to keep recreational users comfortable and healthy. Cold/moist zones typically need insulation, good translucency for solar gain and an understanding of how to remove moisture. Hot/arid zones need structures that can provide shade and UV protection, and are able to accommodate the extreme temperature differences that occur between night and day. Hot/moist zones need good air circulation.

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