When Hurricane Katrina whipped through Delisle, Miss., she was a Category 5 storm, hurling debris and trees and creating a 27-foot surge of water. No one in her path was safe – except for a DuPont hurricane crew holed up in a steel-reinforced, concrete dome.Katrina caused more than $100 million of damage to the Delisle DuPont plant, said David South, the founder and president of Monolithic Constructors Inc. But the monolithic dome that South had built a year earlier as a hurricane shelter withstood Katrina’s wrath and provided a secure and comfortable fortress for 30 DuPont employees.South said that since Hurricane Katrina reached land, the Monolithic Dome Institute’s Web site has received 8 million hits, similar to the number of hits received in 2004 after a monolithic dome in Pensacola, Fla., stood up to Hurricane Ivan.According to a news report by NBC Correspondent Kerry Sanders, who rode out Ivan in the Pensacola Beach “Dome of a Home,” three surrounding houses were destroyed and others were severely damaged by the “300-mile-an-hour winds.”So, is the monolithic dome man’s answer to Mother Nature?The monolithic dome isn’t new. It’s been around since 1975, when, after 15 years of research, South developed a way to improve the structural stability of the geodesic dome (the domes of past, created by triangular wood pieces).He received two patents on the process – one in 1978 and another in 1980 – and today South teaches others how to construct the domes during quarterly workshops at the company’s headquarters in Italy, Texas.About 1,400 people have taken the classes, and 300 have built one or more – one man is on No. 80, South said.”My passion is to see its benefits … it’s vastly different,” he said.What’s different is that concrete and steel are the reinforcing structural membranes of the dome.According to the Monolithic Institute Web site, the dome builder starts with a traditional concrete foundation. Then an Airform, a tarp-like material, is inflated and fabricated to the shape and size of the dome, forming the outer membrane of the shell.About 3 inches of polyurethane foam insulation is applied to the interior surface of the Airform, and steel rebars are attached to the foam. Shotcrete, a special mix of concrete, is sprayed onto the interior surface of the foam, embedding the rebar, finishing the steel-reinforced, concrete structure.”Its shape and the concrete and steel makes it weather proof,” South said. “In nature the strongest shape is the egg … round is your strongest shape … lumber isn’t round.”Steve Schelt, a structural engineer in Winter Park, Fla., isn’t familiar with monolithic domes, but concurred that the symmetrical dome resists wind and “causes the least disruption” because of its shape.Stuart Smith, a structural engineer and partner with Pensacola, Fla.-based Schmidt Dell Associates Inc. agreed with Schelt, and said domes are inherently stable – adding that concrete and steel are a plus.He is familiar with the Pensacola Beach monolithic dome.”Concrete structures do well at the beach,” Smith said. “Certain buildings have better survivability than others.”But nothing is guaranteed against wave pressures or storm surges, he said. “And you can build something like the dome, but what will it cost?” he asked.The monolithic domes are affordable, South said. The costs involved are “very close” to building a traditional home, he said.”A nice two-bedroom, two-bath, 1,000 square- foot home would cost about $100,000,” South said. Financing a dome is getting easier, he said.”Wells Fargo does quite a few, and there is another company in Seattle,” South said, “but it usually requires at least 20 percent down.”South added that “domeowners” save an average of 50 percent on energy costs. Monolithic was accepted as a partner of Energy Star, an energy-rating program sponsored by the U.S. Department of Energy and the Environmental Protection Agency.Environmentally sound, fireproof, hurricane-proof and bug-proof: Why aren’t more homeowners building the monolithic dome?”It’s a perception,” South said. “It’s that herd instinct that we have to look like everyone else.”
