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


Sticks and steel

True enclosure—creating a conventional building—around an existing pool—remains an option as well. This may appeal to users looking for more of an "inside" feel, those seeking unconventional design elements, or those who want to incorporate amenities such as locker rooms or fitness areas, Meus says. Stick-built facilities can use wood (cedar is a popular choice for its water resistance and warm look), glass and steel.

When properly painted with water-resistant paint, steel can hold up to a harsh pool environment—"aluminum could probably last hundreds of years, but when you treat it right, steel might last 120 years," says Meus—but count on careful, costly maintenance to make it work. The moisture-resistant paint, which also is used to coat the insides of water towers, can actually cost more than the steel itself, Dodson says, who used to install steel systems and requires an experienced, specially trained painting contractor to handle it.

Mixing air and water

Each method has its advantages and disadvantages, but any enclosure system brings a whole new set of issues to your pool. Turning outside in magnifies water and its aquatic partner, chlorine. The two combined create the twin nemesis of maintenance: humidity and corrosion. To combat them, a powerful—and appropriate—heating, ventilation and cooling system that balances chemistry, comfort and efficiency is a must.

"We always suggest a true dehumidification system," Christie says. The humidity inside a pool structure should be kept to between 50 percent and 60 percent, he says. While the powder-coated aluminum systems are designed to withstand moisture, a high humidity level can bring a swamp of troubles in many other forms, even to the point that it creates fog indoors.

As pool water evaporates, it brings a gaseous form of chlorine into the air, Dodson says. And since chlorine is heavier than air, the chlorine vapors hang most heavily over the water, creating that "pool smell" that lingers right at nose level without proper ventilation. The most effective ducting and ventilation systems push air away from the pool's surface, where most chlorine fumes are suspended, and pull a regular supply of fresh air inside.

Because of this, the ventilation system and its accompanying ductwork should be planned hand in hand with the enclosure. Ideally, ducts should run at ground level to push the most chemical-laden air away from the pool, Meus says, with more air ducts along the ceiling.

Enclosures with retractable roof systems can ease the load on an HVAC system. At the Mission Valley YMCA, for example, dehumidification consists of opening the roof to let in the dry desert air. The roof openings act as effective, adjustable venting systems as well, Dodson adds, where just a few can be opened to maintain a desirable indoor temperature loss.

Additionally, the sunlight entering the polycarbonate roof helps break down the chlorine gases in the air, eliminating the smell associated with indoor facilities, he says.

Which system works for you?

Deciding which system works best for your facility is a matter of number crunching and research. Glass enclosure systems, along with stick-built additions, require a significant amount of capital. It pays to crunch numbers and see if the additional revenue generated would support the initial expense. Next, talk to the people who know best—other recreation facilities that have enclosed their pools with a variety of systems.

By seeing what different enclosure systems offer, and how they work for a facility, you can make the choice that's best for you and take your aquatic program inside.