Steven Derse, the owner of a corporate travel business in Nashville, Tenn., cannot feel his house move, but he can hear it.
“It’s an eerie creaking sound,” he said, and it echoes throughout his two-story Georgian-style house.
It started two years ago when a severe drought contracted the soil beneath the foundation, which caused it to crack and sink, pulling the house down with it.
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The noise has continued intermittently, becoming more insistent last year when flooding pushed the already compromised foundation and house back upward.
This seesawing effect was noisy and expensive. Derse has spent more than $10,000 to install subterranean piers to stabilize his foundation, and he expects he will have to install more to prevent further cracking and crumbling.
“You lose your sense of security,” he said. “You love your home and then it literally turns on you.”
His is not the only house buffeted by shifting soil. Extreme weather possibly linked to climate change, as well as construction on less-stable ground, has provoked unprecedented foundation failures in houses nationwide.
Foundation-repair companies report a doubling and tripling of their business in the last two decades with no letup even during the recession
“We’ve seen a tremendous influx of pretty severe cases due to either drought or too much rain,” said Dan Jaggers, vice president of technical services at Olshan Foundation Repair, which has offices in the South, Midwest and Great Plains.
“People call panicked because they’ve got gaping cracks in their walls, tile breaking, grout popping and they don’t know what to do.”
Other telltale signs of foundation failure include doors and windows that will not close, chimneys or porches separating from the house and bowing basement walls.
After a particularly dry summer followed by deluges in the fall, Psonya Wilson, a lawyer in Brandon, Miss., noticed light streaming in where the wall had separated from the baseboard in the bedroom of her 5-year-old son.
“I could stick my finger through it,” she said. “I couldn’t believe it. The whole back part of the house had sunk about 6 inches.”
To stop further collapse, not to mention to control the draft, she is having several stabilization piers installed to shore up the foundation of her two-story garden style house; it will cost more than $5,000.
Clay soils, like those beneath the houses of Derse and Wilson, shrink during droughts and swell during floods, causing structures to bob.
And because sandier soil loses its adhesive properties in dry conditions, it pulls away from foundations.
Heavy rains cause it to shift or just collapse beneath structures. With both kinds of soil, such sinking, called subsidence, usually happens gradually, said Randall Orndorff, a geologist with the U.S. Geologic Survey.
But, he said, “swinging from very wet to extremely dry weather like we’ve been seeing lately in many parts of the country may be accelerating the effect.”
Subsidence is not covered by most homeowners’ insurance policies in the United States, unlike in Britain, where the increasing number of homeowners’ claims due to foundation failure prompted the Charter Insurance Institute, an industry-trade group, to issue a dire warning about the financial drain in its 2009 report, “Coping with Climate Change: Risks and Opportunities for Insurers.”
“The question we need to ask is, are we building to cope with the enhanced weather events related to climate change,” said Brenda Ekwurzel, a climate scientist with the Union of Concerned Scientists, a nonprofit group advocating science-based solutions to environmental and health issues.
“It’s obvious that we need to look at changing building codes worldwide to deal with this.”
Compounding the problem is that, during the recent housing boom in the United States, houses were built in areas where the soil was particularly prone to shift.
“If you think about it, the best ground in cities is usually taken early on, so the builders and developers have often been expanding into less-desirable areas, and in their rush to make money, may not have designed structures to deal with it,” said David Lourie, a geotechnical engineer in New Orleans.
Fixing a failed foundation usually involves hiring a foundation-repair company to install cement or steel piers around the perimeter of the house’s slab or near its existing piers if it is a pier-and-beam foundation.
Once in place, hydraulic jacks lift and level the house and transfer its weight to the new supports.
The cost depends on the severity of the problem but generally runs about $1,000 to $2,000 per pier, which should include a lifetime transferable warranty.
“It’s amazing to watch your house get jacked up like that,” said Miguel Rivera, a designer of heating and air-conditioning systems, who had to pay $13,000 to have his 60-year-old house in West Orange, N.J., shored up in January.
“It’s just immediate. You’re like, ‘Whoa, up it goes.’ “
His dining room began separating from the rest of his house about five years ago after repeated heavy rains shifted the earth beneath it.
The problem was made worse when he removed a nearby tree, which was probably siphoning off excess water and providing structure to the soil beneath his house.
“It often happens that you upset the moisture and structural balance when you knock down or tear out trees,” said Lourie, the geotechnical engineer, adding that planting trees too close to the house can be harmful. “Plant them at least half their mature height away from the house.”
Landscaping should, as a rule, be installed so that water slopes away from the house and gutters should discharge at least 5 feet from the house to avoid oversaturating the soil.
During droughts, experts recommend placing soaker hoses around the perimeter of the house and turning them on 30 minutes a day.
“The idea is to maintain a constant amount of moisture in the soil,” said Tom Witherspoon, a foundation engineer in Dallas. “If you can do that, your house will never move.”