Tue, October 26, 2021

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Designed for disaster: These homes can withstand a Category 5 hurricane


Looking at a brochure from Deltec Homes feels like watching an episode of HGTVs "House Hunters" - beachfront homes with ornate patios and panoramic windows overlook pristine ocean views.

It's hard to believe that the same quaint, debonair homes are built to withstand Mother Nature's ultimate test - a Category 5 hurricane.

It's something they've done before, and will inevitably do again. And, in an era marked by strengthening storms and rising seas due to climate change, Deltec Homes has made a business of building for the extreme.

Deltec is one of a number of companies that designs, builds and sells custom hurricane-proof homes. The group was born in the 1950s when two brothers - one an engineer at Oakridge National Laboratories and the other an entrepreneur - began experimenting with the idea of marketing homes designed to survive the inconceivable. Since then, Deltec has contributed to the design installation of more than 5,000 homes worldwide.

Unlike other hurricane-proof homes, which are typically modular and often bunkerlike, Deltec's homes are all custom-built. They design each structure at their facilities in Asheville, N.C., contracting out with local builders to assemble the final product to the customer's wishes.

"Each home that we build is essentially custom-designed using a series of what we call building blocks," said Steve Linton, a degreed engineer and the president of Deltec Homes. "There are 10 sizes of those panoramic homes. People can design whatever they want and connect them with other structures."

Older residents may prefer single-story elongated ranch-style homes, while others may want a three-floor beach house with lots of natural light and windows facing the water. Deltec has refined their engineering over the years to be able to do it all. That's meant a lot of time at the drawing board.

"Obviously the shape matters," explained Linton. "It's a round home. It's aerodynamic to the point you get about 30 percent less pressure that builds up against Deltec home versus a conventional home."

In other words, the shape of the house helps deflect air flow around the structure rather than absorb that force, no matter which way the wind is coming from.

"The second piece is the materials that go into the home," continued Linton. "We look at optimizing the materials ... to all be about twice as strong as in a typical home. Every board is tested for strength. The plywood is twice as strong and the metal connections we use are made in a completely different fashion."

Joints and connections are typically a failure point in structure when they're subjected to high winds. That's seen especially often in surveying the damage left by tornadoes. Poorly-anchored roofs take off when wind passes overhead, lifting like airplane wings in response to relative low pressure generated over the structure. After that, it's only a matter of time before exterior walls fail, leaving the bones of the house susceptible to flying debris.

Deltec's homes have encountered top-tier hurricanes like Michael, a Category 5 that hit the Big Bend of Florida on Oct. 10, 2018, and Dorian, which lay siege to the northwest Bahamas in early September 2019. All have fared well, escaping with minimal damage.

Josh Morgerman, among the world's top hurricane chasers and star of UKTV's and BBC's Hurricane Man, became a brand ambassador for Deltec after surviving the eyewall, the zone of strongest winds as high as 185 mph, of Hurricane Dorian on Great Abaco Island. He had heard that the homes built by Deltec were still standing after the storm. He had to learn more.

"At first, I was very skeptical," said Morgerman. "But they gave me a very detailed Excel spreadsheet that was pages long of where their houses are along the Gulf Coast and the Bahamas. I found the ones that had gone through the eyewalls of (Categories) 4 and 5, and some that had perfect direct hits. There were a few that went through Dorian's right front quadrant of the eyewall. I reached out to the homeowners and interviewed them."

Morgerman learned that both homes emerged with only minor scratches and dings, primarily in the form of cosmetic damage.

"Those houses had survived the ultimate test," said Morgerman. "Dorian was the hurricane of hurricanes. If a house can sustained that, this product's for real."

Dick Love, who lives in Florida, owns a Deltec home on Scotland Cay, just north of Marsh Harbour in the Bahamas, that survived Dorian. Of the 62 homes that one stood there, only three escaped with minimal damage - Love's, and two others built by the same contractor.

"The house to the left and to the right were obliterated," said Love. "All that was left was the foundation. The only damage to my home was a couple roof shingles, and then (a piece of wood from) the neighbor's home that was next door. It was attached to his roof and went through the side wall and the inner wall and went through the living room and hit the other wall twenty-five feet away."

Wind gusts on Scotland Cay were estimated to have topped 180 mph.

"It looked like an atom bomb went off," said Love. "For the other homes, it wasn't just that all four walls were gone, the furniture was gone ... the refrigerators, freezers in the houses were nowhere to be found. Everything was blown into the sea. It's indescribable."

A Deltec home remains standing in Mexico Beach, Fla. following the passage of Category 5 Hurricane Michael in October of 2018. MUST CREDIT: Deltec

Love has lived through four hurricanes in Florida, including Jeanne and Frances in 2004. He wasn't on Scotland Cay when Dorian struck, something he says he's thankful for.

"My home had 175 mph rated Deltec shutters, and they survived but with huge bashes and dents in them," he explained.

After some small repairs, Love's home is now good as new.

Matt Oblinksy, Deltec's director of engineering, spearheads an effort to constantly find better building materials to further strengthen its designs.

"After each and every hurricane ... we reach out to each and every homeowner in the path of a storm to ask how they are," said Linton. "99.9 percent of the time we're seeing 'we lost a couple shingles' or 'we lost a piece of trim, but our neighbor's home was demolished.' Our homes have been field tested for a number of years."

Deltec allows customers the flexibility to customize their homes. About two thirds of homes they produce are one story, with the remainder generally two floors. Once in a while the company builds a three-story structure, but those are rare, and usually for commercial purposes. Three stories is the limit. Many customers opt for impact-resistant windows.

Hurricane-proof homes are designed to protect inhabitants from the wind, but nothing can counteract the power of water. That's why the homes are located to avoid storm surge flooding.

"We do homes up on pilings to elevate them to avoid storm surge," said Oblinsky. "We highly recommend two feet above flood elevation to protect them from those situations."

The company also has a propriety anchoring technique that ensures homes remain firmly affixed in place no matter what Mother Nature throws their way.

Leslie Chapman-Henderson, president of the Federal Alliance for Safe Homes, or FLASH, said hurricane-resilient homes like Deltec are worth the price in the long run.

"Often in the industry people will talk about price point as the purchase point," explained Chapman-Henderson. "We urge homeowners to consider that the house isn't just what you pay for it the first day ... it's the time horizon after the hurricane. The homes that are really the most affordable are the ones that survive the storm."

Chapman-Henderson, whose organization closely studies the recovery process after major storms, says that aspect of storms is rarely talked about - and lasts long after the television crews and reporters leave.

"We have a project we're doing on hurricane Michael. We still have hundreds of families who are not back in their home," she said. "To us that's the cost."

Even for residents who can't afford a hurricane-proof home, there are plenty of tactics for fortifying your home. Many, said Chapman-Henderson, can be done for under $50.

"The cost of these things is so minuscule," she explained. "A couple handfuls of additional nails that keep the roof there when you need it, for instance."

Deltec isn't the only company marketing hurricane-proof homes to consumers. Fox Blocks Insulated Concrete Forms, headquartered in Omaha, helps build hurricane-proof structures too, but they take a different approach.

"We are an insulated concrete form manufacturer," said Mike Kennaw, Fox Blocks' vice president. "We basically manufacture, produce, sell and market the insulate concrete form, which is part of a steel reinforced wall assembly, and the testing we have done for poured-in-place concrete walls has shown that we have very high wind test rating."

The concrete can be one hard shell, meaning fewer failure points, and is more impact-resistant than traditional wood homes. When it comes to roofs and interior walls, however, that's up to the individual builder.

"We are a component of high wind construction," explained Kennaw.

 

Building a hurricane-proof home may cost you a pretty penny, but it's something people like Chapman-Henderson advocate could pay for itself over time. Meanwhile, forecasters are looking forward to what will likely be another anomalously busy hurricane season. The National Hurricane Center began issuing its daily tropical weather outlooks on Saturday.

Published : May 16, 2021

By : The Washington Post · Matthew Cappucci