(Bloomberg) — In the last year alone, floods have washed away almost a million homes in Pakistan, heat waves have claimed hundreds of lives in poorly air-conditioned London, and Hurricane Ian has destroyed homes on the US East Coast. From record temperatures to wildfires and gale-force winds, homes around the world are being tested in a changing climate.
Climate impacts also increase the cost of insuring homes against these threats. In the US, for example, a survey last year by online insurance marketplace Policygenius found that 90% of more than 8,000 insured homes saw premium increases, up 12% on average in May from a year earlier. Growth was sharpest in disaster-prone states, including Washington, Colorado, and Arkansas, each of which saw premiums rise by about 18%.
At the intersection of concerns about climate impacts and insurance premiums is a growing group of companies focused on developing more sustainable housing, including architectural designs more suited to surviving water, fire and wind.
“Resiliency is important,” says Ann Cope, chief engineer of the Insurance Institute for Business and Home Safety (IBHS), a South Carolina-based nonprofit research institute that advises builders and homeowners on climate-resilient building. “It’s a matter of adapting and understanding the climate we live in and being prepared for it, so a bad day is not a tragic day.”
Here are four examples of architectural solutions designed to better withstand climate impacts.
The house that floats in the floods
Following the devastating floods in Japan in 2015, real estate developer Ichijo Co. designed a “houseboat” to protect against future threats. When the water level exceeds approximately 1 meter (3.3 feet), the entire building rises to the surface of the water. When the water recedes, the building returns to its original position with an error less than the length of a human thumb, thanks to four pillars that connect the house to the ground and stabilize its movement.
Ichijō makes another design of his house that does not float, but instead channels flood waters into a designated interior flood zone to reduce damage once the water level rises above 1 meter. Both designs are equipped with watertight windows and doors, as well as a special drainage system to prevent overflow in the kitchen, toilets and baths. The company says it has built more than 1,000 flood-resistant homes since 2020, but did not say how many of its sales came from houseboats.
House to protect from heat (or inside)
In Castle Rock, Colorado, a house nestled among the hills looks just like any other: gray facade, pitched roof, lots of windows. But the walls of this particular home, designed by Golden-based startup Colorado Earth, were built from pressed earth blocks made mostly of sand and clay. Colorado-Earth engineer Lisa Maury has adapted a technique that originated in ancient Jordan to meet modern building codes. This creates walls that are essentially fireproof – an irony since the house is owned by the local firefighter.
Maury says the slow pace at which heat transfers through the house’s 10-inch-thick walls (about one inch per hour) means they’re also good at keeping heat out during cold weather and outside during hot weather. In Castle Rock, where February temperatures dip to an average low of 18F (-7C), sensor data collected by Colorado Earth showed an entire home staying at a constant 68F (20C) with sunlight and a wood-burning stove.
A home that can withstand a hurricane
Deltec Homes in North Carolina is known for its homes that can withstand winds up to 190 mph. Now the company is looking to up the game: Deltec’s latest model, still in development, is rated for winds up to 225 mph.
Deltec attributes the stability of its structures to a largely curvilinear shape that helps offset wind pressure by about 30%. The company says it also selects construction materials that are twice as strong as building codes typically require.
As storms intensify, interest in Deltec homes is growing, with the company’s president saying sales are up about 50% since 2018. To date, Deltec has built over 5,500 hurricane-resistant homes in 32 countries, including this 2,616-square-foot home. in San Salvador in the Bahamas.
House with power under fire
Wildfire is one of the most common climate disasters in the US, with one in five single-family homes at risk of experiencing a fire over the next 30 years. That’s why IBHS offers step-by-step instructions for building a wildfire-ready home.
After losing his Paradise, California home in one of the deadliest wildfires in U.S. history in 2019, Gary Ledbetter, 59, used IBHS guidelines to publicize his recovery with one goal: never see it burn. This means using a lot of fire resistant features that start at the top. Ledbetter’s new 2,200-square-foot home has a roof known as “Class A,” the highest fire rating, and is fitted with sprinklers. Fireproof vents and fire doors have also been installed.
Being prepared for wildfires also means rethinking the landscape. Ledbetter avoids window flower boxes that could potentially catch fire in a fire. Instead, his home is surrounded by a 5-foot non-combustible area of concrete and gravel.
This preparation comes at a price: for example, Ledbetter fireproof garage doors cost about 50% more than conventional ones. But he says the upgrade has allowed him to insure the house, something residents of this wildfire-prone city can’t take for granted.
“Most companies won’t write policy in heaven,” he says. “If we didn’t have all the improvements and efforts to build a sustainable home, the underwriter probably wouldn’t have touched us.”
To contact the authors of this story:
Coco Liu in New York at firstname.lastname@example.org
Grace Huang in Tokyo at email@example.com