When the Pacific Palisades fire reached the elite stretch of Malibu coastline known as Carbon Beach last month, British investor Simon Nixon was in London, 5,400 miles away from where the flames were approaching his house. Helpless to do much but wait for updates, he finally heard from someone at the local fire department, who sent a photo via WhatsApp. Sixteen houses in a row to the west of his were significantly damaged or destroyed, including those of billionaires Herb Simon, Mark Walter and Geoffrey Palmer—but miraculously, Nixon’s was still standing, and even seemed to have acted as a fire curtain that protected six neighbors on the other side. “You saved every house to the right,” the employee wrote.

Carbon Beach, often called “Billionaires Beach” for its prevalence of high-net-worth homeowners, lies at the southwestern perimeter of the Palisades fire, across the Pacific Coast Highway. The blaze consumed most houses on the eastern half of the beach, but Nixon’s escaped with less than 10% damage, according to the LA county inspection map. The reason for his good fortune? His rectangular, industrial-looking property—aptly nicknamed “The Fortress”—was made primarily of concrete, steel and glass. Nixon built the property about a year ago after razing two aging wooden homes he’d purchased there for $24.6 million in 2016.

“If I built a wooden house, it wouldn’t be there now, no question,” says Nixon. The tech entrepreneur, who earned the bulk of his estimated $2 billion fortune by cofounding the price-comparison website MoneySuperMarket, runs a business called Simon Escapes in which he develops luxury houses for short-term rent. Its seven-property portfolio stretches from Barbados to South Africa; The Fortress is the only U.S. offering. He’d been renting out the five-bedroom home for more than $200,000 per month, but it was unoccupied at the time of the fire.

The architect behind The Fortress is the esteemed Seattle-based outfit Olson Kundig, which is perhaps better known for designing museums and renovating Seattle’s iconic Space Needle than for fashioning houses. Among its recent projects: The Children’s World of the Jewish Museum Berlin (ANOHA), which features a 6,300-square-foot circular wooden ark, and the LeBron James Innovation Center at Nike’s Oregon headquarters.

Nixon spent over $1,700 per square foot (more than $15 million) on construction—pricing that he locked in before the pandemic, he says, adding that costs have since risen significantly. Kundig’s stark, boxy style stands in contrast to the older and softer look of most of Carbon Beach: Many properties there were constructed between the 1920s and 1970s, when “all the U.S. really built was wood,” says broker Nathaniel Pitchon Getzels of Coldwell Banker. That includes three of the six billionaire homes that were wrecked. Nixon, though, estimates he has just $400,000 worth of damage, mostly to the wooden deck and glass balustrades. That’s equivalent to just 1% of what he spent to buy and build the property. His house may be a model for how to build back stronger—not only there, but across Los Angeles.

Nixon didn’t have wildfires in mind when he developed The Fortress. “I thought the higher likelihood would be tsunami, earthquake, maybe mudslide,” he says. The water on one side of the beach and the Pacific Coast Highway on the other help impede fire spread, but strong gusts—like last month’s infamous Santa Ana winds—can still toss embers and flaming debris across the highway.

Instead, says Nixon, “part of the reason behind the design was that the environment can be so harsh there,” noting that the highway brings noise and air pollution. The side of the house that faces the road is entirely concrete to mitigate those factors. Exposed steel beams provide support throughout. Meanwhile, the side facing the ocean is made of glass to maximize the view, but can be enclosed with motorized exterior shutters.

“I’m not surprised it survived. Concrete doesn’t burn,” says Victor Sanchez, a retired firefighter who worked in the Malibu area for 25 years, including a stint at the Carbon Beach station. Concrete buildings are all over California, but are almost always commercial properties. “It’s not common for a single family dwelling. But Malibu is not a common place. Obviously billionaires have more money to get more expensive construction like that.”

Another Carbon Beach resident whose home withstood moderate damage thanks—again—to concrete was Grant Cardone, a real estate and private equity investor. In his case, it was a concrete foundation that juts over the beach to elevate the house above the ground. The flames came from below, he says, and were stymied by the foundation long enough for the fire department to put them out before they consumed the wooden part of the house. (Still, there was enough damage that he plans to spend $30 million reconstructing from scratch—this time either with metal, stone or concrete.)

Building with concrete often adds 5% to 10% to the cost of construction, according to the National Ready Mixed Concrete Association. However, many concrete homeowners see long-term savings thanks to greater energy efficiency and lower insurance premiums. Plus increasingly extreme weather, from the fires to the recent mud slides, is pushing architects and home owners to think hard about materials that might best hold up against Mother Nature.

The houses on Nixon’s western side that burned down—including Herb Simon’s and one of Geoffrey Palmer’s homes—generally had wood frames and stucco exteriors, like many properties in the Los Angeles area. The fourth richest person in the world, Larry Ellison, also lost two of his homes on Carbon Beach, worth a combined $39 million, that appeared to have had wooden frames. Wood’s elasticity makes it resistant to earthquakes, another natural hazard California faces, but not fires by any means.

“With a wood frame stucco, embers will get in the eves and blow into the ventilation hole, and if it gets into the attic, forget it, you can’t save it,” says Sanchez. “Because it takes a whole lot of manpower to put out an attic fire, and we got hundreds of homes burning. It’s just impossible to keep up with that.” He notes that the houses on Carbon Beach are also packed tightly together, making it easier for flames to jump between them.

Some homebuilders say they’ve found a way to make concrete viable for the mass market. Nixon’s house is made more expensive by steel reinforcement and the fact that the concrete is “cast-in-place,” meaning that it’s poured at the construction site. The company NileBuilt, on the other hand, makes concrete walls offsite and assembles them at home lots within hours. Founder Scott Long says they’ve developed a lightweight new technology—an advanced fiber composite reinforcement—that doesn’t require a steel skeleton, bends like wood during earthquakes, doesn’t combust, and is cheaper than a wood home.

“Housing is the only industry that has not advanced construction practices, ever,” says Long. “We’re building exactly the same way we did when we started using dimensional lumber in the 1400s. It’s a dinosaur of an industry.”

Architect Rebecca Ascher agrees that innovation is desperately needed. Another costly challenge with concrete is creating cavities for plumbing and wiring, she says—but that may become less relevant as homes are outfitted with alternative energy sources. “We’re kind of in that in-between zone between old-fashioned life and some futuristic, George Jetson life,” she says. “And maybe it’s catastrophic events like this that force the changes.”

No matter the cost, there are still plenty who have no interest in concrete. “Most people don’t like it,” says Ascher, whose firm Bex Ink caters to ultra-wealthy clients. “It has a lot of imperfections. It has a textural quality. It’s echoey. It’s cold to the touch. I’m not saying that advancements can’t be made—100 years from now, people could be laughing about the way concrete used to be. But it needs some loving before it becomes more widespread.”

Los Angeles now faces the gargantuan task of rebuilding. California Governor Gavin Newsom signed an executive order last month meant to streamline the process, in part by suspending some environmental rules. Officials are also debating possible new homebuilding regulations, including rezoning for lower housing density in especially fire-prone areas, and expediting a set of forthcoming standards for removing debris, flammable vegetation and wooden fences from the perimeters of homes. Concrete, after all, isn’t a panacea. “It certainly doesn’t hurt to have concrete walls, but if we just build out of concrete and don’t change anything else, we’re going to continue to lose lots of homes,” says retired fire chief Dave Winnacker.

As for Nixon, some say he also had a bit of luck: had embers gotten inside, they would have lit up anything flammable. Regardless, he’s hoping his neighbors reconstruct with fire-resistant materials—which he notes will also make his house less vulnerable.

“I try to look at positives,” he says, “and the only positive I can think of for Carbon Beach is that if you take a five- to ten-year time period, hopefully most of those houses will have been built back in a more contemporary way. Some of them did look quite dated, and were maybe not suitable for the climatic changes that have occurred over the last 100 years. The beach in ten years’ time could look fantastic, and be one of the best beaches in the U.S.”