Facility Profile - November 2002
Find a printable version here

Dome Provides Plenty of New Space to Roam

Hononegah High School Field House
Rockton, Ill.

By Jenny E. Beeh

When Hononegah High School in Rockton, Ill., was badly in need of some elbowroom for its physical education classes and practice space for its sports teams, it decided to think, well, outside the box. In fact, there's not really a box at all: The school chose an inflatable dome, the first in Illinois high-school history.

Of course, many factors led up to this big milestone.


First of all, talk about growth spurts, the Hononegah High School student population grew 49 percent from 1,157 pupils in 1991-1992 to 1,719 in 2000-2001. This student population explosion, combined with more rigid state regulations for physical education classes requiring more students to take P.E., had the school scrambling.

"Our need came from a lack of physical education classroom space within our district," says Dr. Ralph Marshall, Hononegah superintendent. "The other issue was that after school our sports teams and band were already using up any available indoor recreation space."

There simply was not enough room to fit the scheduling of daily practices and activities.

"We had kids here until 10 p.m. at night," he says. "From an education standpoint, we didn't think that was a good idea."

With space at a premium in the school, so was money in the budget.

"We were also faced with limited funding," says Marshall, himself a 1970 Hononegah graduate. The school district looked at more "traditional" building options of brick and mortar or steel structures. "But the cost was excessive," he says of that option's $6 million price tag. "There were not the funds for the space we needed. We had to look at other alternatives."

The alternative they chose was a permanent, air-supported dome, which could provide twice as much space for about half the cost of the brick-and-mortar options.

Spanning 330 feet long, 180 feet wide and 50 feet high, the new field house dome boasts 59,400 square feet (about 1.3 acres) of new indoor recreational space, plenty for an eight-lane, 200-meter track and four full-size basketball/volleyball courts. The dome was designed by Air Structures American Technologies Inc. (ASATI) of Rye Brook, N.Y.

Incidentally, the $3 million project costs included not only the dome structure and labor (about $1.2 million) but the foundation, flooring and lighting as well as adding a 71-stall parking lot and resurfacing the existing outdoor tennis courts.

"We expanded what we were able to do with our funding," Marshall says. Such a great span of open space also gives the school a lot of options for a flexible layout.

"For example, we could turn it into a large arena or put two large tennis courts in the center," Marshall says. The dome is also periodically available for community use and special event rental, like an expo.

While some members of the community may have had doubts when the dome was first proposed, most of those concerns have been put to rest—especially about the dome's appearance when the decorative fencing and landscaping were put into place.

"It can be made much more aesthetically appealing than a giant marshmallow," he says. The dome is definitely growing on the community.


"To anyone who has gone in and seen it, the biggest thing I hear is that it really is a substantial structure: 'It's like a real building,'" he says of the typical reaction.

Yes, Virginia, it is a real building. And it meets all the required codes.

"From the foundation down, it's the same as a traditional building," Marshall says. "The only thing that's changed is our roof comes down to the floor. Our roof really has a great slope to it. They can feel safe and secure inside."

Initially, some school planners were worried about the dome's durability and longevity.

"We have some unknowns yet," says Marshall of the dome's potential life span, which is estimated to be about 15 to 20 years. So planners made sure to factor in the cost of replacing the dome's fabric skin (about 30 percent of the district's original cost) down the road.

Intended to be a permanent structure attached to the school, the dome field house was designed to withstand winds more than 100 mph and snow loads greater than 30 pounds per square foot, or about three feet of heavy snow to six feet of light snow. The first month it was up, the dome experienced 70-mph winds and an 18-inch snowstorm without problems. The curved structure allows the snow to shed off, and if needed, the heat can be turned up inside to help melt the snow.

Grids of cable and air blowers outside the dome support the vinyl-coated polyester cover. The blowers create high volume and low pressure to hold up the dome.

The energy cost incurred by the blowers is basically a trade-off for the dome's lower maintenance and lighting costs, compared to a more traditional structure. The dome's skin in virtually maintenance-free while the natural translucency provides good lighting, especially on sunny days. The soft inner shell allows for good acoustics as well. Operating costs for Hononegah's dome are estimated to be about $53,000 per year.

"I would highly recommend it to meet your needs in a cost-effective manner," Marshall says.

For more information
Air Structures American Technologies Inc.: 858-454-1777
Or visit www.airbldg.com