Instant Dome? A unique construction project in Hennessey, OK gave the town one of its largest buildings in less than 2 hours.

HENNESSEY, OKLAHOMA -- It was hard to tell what was happening in the dark before school in Hennessey.

Christmas lights were still blinking in the distance.

But as the light came up so did the largest soft sided dome ever inflated.

School Supt. Mike Woods and everyone else watching could scarcely believe their eyes.

"What do you think," asked a visitor to the construction site?

"I think we didn't have a building here about an hour and a half ago and now we do," Woods responded.

Over the past several weeks Wynn Construction and South Industries dug a circular footing, hauled in a huge plastic skin, and prepared for this day.

Inflatable domes aren't uncommon as a modern construction technique but inflatable walls too, and on this scale?

Never.

Construction superintendent Ron Sorenson explained, "The dome is approximately 180 feet in diameter. The stem wall is 28 feet tall."

That was why he was so nervous about any hint of wind.

"There's so much fabric it acts like a sail," he continued. "So the whole building can shift any way."

"That rail is 30,000 pounds, but as of now everything went perfectly according to plan without problems. So the stress level has gone from up here to practically nonexistent."

The whole inflation process took just over 90 minutes.

The next step, spraying insulation inside, then hardening the structure with rebar and sprayed concrete.

"This hasn't been done before on this scale," said Supt. Woods

He's hoping to hear balls bouncing inside before Thanksgiving, 2019.

"This is a fully rated FEMA structure so we not only got a safe place for our kids but we were also able to build a facility for basketball and volleyball."

The rest of Hennessey witnessed the instant birth of its largest structure, 70 feet high, a seating capacity of nearly 2,000, inflated like a big balloon in one December morning.

School officials at the construction site estimate the total cost of their new dome at $9 million, with a substantial decrease in cost and time of construction thanks to these new methods.

Notice: you are using an outdated browser. Microsoft does not recommend using IE as your default browser. Some features on this website, like video and images, might not work properly. For the best experience, please upgrade your browser.