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Sinkholes have wreaked havoc on a Keystone home. But a complex procedure raises the foundation, hopefully reparing the damage for good.
By JOSH ZIMMER
© St. Petersburg Times, published October 26, 2001
KEYSTONE -- The cracking by the office window was a first sign, Jan Fowler said.
Then, as the weeks went by, the various fractures in her comfortable Crawley Road home began to add up: hairline cracks in the kitchen tile floor, the obvious gap in the bedroom where the wall and ceiling meet, and shifting so bad that one bedroom window separated from the wall.
On tours of the house, Fowler also doesn't miss pointing out how the corner lamp near the fireplace tilts toward the backyard pond, the result of a depressed living room floor.
The frustration, building up since March, finally reached the point where she contacted her insurance agent in July.
"We didn't think it could be anything other than normal settling," she said. "Then it got worse and worse.
Liberty Mutual offered to pay for a firm to address the settling by shooting grout underneath the house. But instinct told Fowler the method was more of a Band-Aid than a solution.
Checking the Yellow Pages, she found a structural engineer who conducted tests around the foundation. The firm -- Award Engineering, Inc. of Tampa -- came back with bad news: Her home, which she shares with fiancee Greg Colvin and her daughter Vanessa Cox, was resting on sinkholes. Five to be exact.
She hired the firm, which is using a more complex procedure to raise the foundation. Although the damage was greater than initially expected -- the entire foundation had to be lifted 3 inches instead of 11/2 inches -- Fowler said she is confident the home is sitting now on terra firma.
"That house will never, never move again," she said. The job was in its final stages this week, although Fowler anticipated landscaping and driveway repairs ahead.
Although less prone to sinkholes than areas of Pasco and Hernando counties, Hillsborough County does have a combination of geography and demographics that can lead to sinkholes, experts say.
Rain, drought and well pumping all upset the earth underground to the point that the ground gives way.
"We're sitting on top of limestone and the limestone is riddled with cavities," said Tony Gilboy, sinkhole coordinator for the Southwest Florida Water Management District. "Over time those cavities enlarge and the material that is sitting on top of the limestone typically will collapse into the cavity."
The frequency of sinkholes is sufficient enough to have spawned an industry in sinkhole litigation. That's where lawyers like Alan Marshall of Palm Harbor come into the picture -- literally. There are large billboards advertising his services on U.S. 19, Gilboy said.
In Florida, insurance companies are required to provide sinkhole coverage under normal homeowners policy. Confusion arises, Marshall said, when experts hired by an insurance company say sinkholes are not responsible for cracks and other kinds of house shifting.
Since insurance companies almost always accept an engineer's analysis, seeking second opinions is the right approach, Marshall said. He also pays for the second report, which the insurance company will not do, anticipating that he will recoup his expenses through litigation.
Sinkhole cases are not cheap. An engineering analysis costs at least $5,000 and taking a case to trial generally requires $30,000 to $35,000, he said.
In Fowler's case, the insurance company agreed to pay for the foundation restoration and appears to be willing to pay for interior and driveway repairs, as well, she said. She estimated the total cost at around $100,000.
"If you have damage to your house from something that looks like settlement, call your insurance company," said Marshall, who has settled cases in Avila and Cheval. "If it doesn't seem right, get a second opinion."
"A lot of homeowners roll over. If they complain, they win."
The apparent consensus among experts is the method being used at Fowler's house is the best way to repair sinkholes.
There workers initially dug 16 deep, angled holes around the foundation using an augur that injects grout into the space. Once the grout sets, high-strength cement is added. When it hardens, metal jacks are placed on top, under the foundation's edge. At that point, the house can be raised.
Workers eventually had to dig 9 more holes than planned because damage was greater than initially thought.
The process, more widespread in Europe, is becoming increasingly common here, experts said.
"That, in combination with the grout, is the state-of-the-art technique in controlling sinkholes around houses," Gilboy said. "That thing's not going to move."
Since sinkholes form at weak points in the ground, Gilboy said people should watch where the water goes.
"One thing I encourage people to do if they have a depression or swale, some place where they have water ponding, is to fill it up," he said. Pooling water "will accelerate the erosion process."
Redirected downspouts can also keep water from concentrating too much in one place, he added.
Fowler is concerned her entire side of the street could be vulnerable to sinkholes. One house to the north had sinkhole repairs in the past, she said, while the sinkhole on the south side of her property extends to her neighbor's house.
She believes pumping from underground water wells has contributed to the problem. Northwest Hillsborough County and Pinellas County, which gets much of the well water from this area, have been growing fast for decades.
"I think the whole neighborhood is falling in a hole," she said.
Well pumping can cause underground pressure changes that will stress sinkhole walls, Stewart said. But foundation shifting can also be the result of poor home construction, he pointed out. And "sometimes the geology just changes on its own."
Amanda Grizzaffe, who lives on the same street as the Fowler home, says "we've been here 10 years and haven't had any problems."
- Josh Zimmer covers Keystone and the environment. He can be reached at (813)-226-3474.