Sinkhole Warning Signs
Sinkholes rarely strike without giving some warning in the surrounding environment or in a nearby home. Here are signs to watch for that may indicate a problem:
- Trees or fence posts that tilt or fall
- Foundations that slant
- New small ponds that appear after rain
- Cracks in the ground
- Sudden drainage of a pond
- Rapid appearance of a hole in the ground
- Dips, depressions, slopes that appear in a yard
- Dead patches of grass or plants
- Sinkholes in the neighborhood
- Wilted vegetation in a limited area
- Well water that is discolored or contaminated with debris
- Cracking or buckling of home’s concrete slab
- Presence of odd bugs like slugs and centipedes in the home
- Earthy odor in home after rain
- New or widening cracks
- Separation between walls and ceiling or floors
- Cracks in interior walls
- Cracks around door and window frames
- Cracked grout between tiles
- Cracked tiles
- Stairstep cracks in blocks or bricks
- Uneven floors, warping of hardwood, bulging or sagging sections
- Doors or windows that don’t open or close easily
- Cracks in sheetrock near doors or windows
All homes are subject to some settling. Any of these signs could exist without the presence of a sinkhole; however, the presence of one or more calls for further careful observation and an abundance of caution.
Angie's List Foundation Repair Award
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The Road to a Remarkable Repair
Earth Tech’s Nine Steps to Successful Stabilization
Travel every mile of the road to a remarkable repair with experienced and friendly Earth Tech team members who have the resources to meet all your needs. These highly trained specialists work closely together every day to exceed your expectations.
You receive verification and a Geotechnical Report from your Insurance Company. Earth Tech also receives a copy of the Report.
Ginger contacts you to briefly describe the process, answer any questions and assign your Project Manager.
Dave our estimator, prepares a proposal based on your report and coordinates with your Project Manager.
Lauren, your Project Manager, contacts you to arrange a site visit and will be your primary contact for the duration of your project.
After you select Earth Tech, your Project Manager will begin the administrative process: Contract, Permits and Scheduling.
Dean leads Earth Tech’s Operation Team and will work with your Engineer to coordinate the start date, assess utility locations and address any issues or prep-work.
Your Earth Tech Supervisor and Crew are on the job. You will be regularly receiving updates from your Project Manager.
The project is now complete. Michelle will guide you through the final paperwork.
Best Sinkhole Repair Methods
Once a sinkhole is discovered and examined, the repair method depends on the size, stability, location, geological context, and the immediate cause of the sinkhole.
In general, a hole that’s very small and very stable in an open area can simply be filled with dirt and restored with ground cover.
A larger hole in an open area is likely to need excavation down to some sort of bedrock for stability, and then a filling operation with layers of rock, gravel, dirt, and possibly grout.
In open areas, it’s always important to determine the depth of the sinkhole and whether the bottom and sides are stable. These tests are carried out using a sturdy stick as a probe.
Initial evaluation is more difficult when a sinkhole occurs underneath any kind of structure. A geological engineer must use specialized equipment to determine the nature and extent of the sinkhole event. Once this is accomplished, the engineer develops a plan to stabilize and restore the building. This plan usually calls for grout of some kind to be pumped under pressure to fill voids and compact soil with rocklike material. This process will be carried out through various techniques of injection grouting that are appropriate to the situation.
Depending on geological conditions surrounding the hole, many different geotechnical approaches could be called upon. But in every case, the goal is to find or create a solid support underneath whatever is on the surface, including ground cover, homes, or buildings.
The repair process always begins with safety. You can learn some appropriate precautions here.
When Your Home Has a Sinkhole
If you notice signs of movement in your home, and you suspect sinkhole activity, there are a series of steps you should take to determine if sinkhole activity is actually present. Remain calm. Remember, major sinkholes are extremely rare, and there are many professionals available to assist you.
Of course, if you see an actual cavity in the ground, you should take steps to make sure anyone who might come into the area stays away from the danger. You should rope off such an area completely, and if there is immediate danger to life or property, call emergency services. Contact your homeowners insurance company as well. You may also ask Earth Tech to come right away to review the situation by calling us at (813) 909-8000 at any hour of the day or night.
When you contact your insurance company, they will ask for information, and if appropriate, they will have an insurance adjustor determine if further investigation by a technical expert is warranted. If so, the insurance company will call in a certified engineer to evaluate the situation and conduct appropriate testing. The engineer will issue a report giving a detailed opinion about the cause of the damage. If there is indeed sinkhole activity, then your insurance company will come up with a repair plan.
Do take comfort in the fact that most sinkholes are not dangerous, and can be stabilized by professionals like the ones you’ll meet at Earth Tech.
Florida Sinkhole Insurance Facts
In Florida, insurance companies are required to provide homeowners insurance coverage that includes damage from “catastrophic ground cover collapse.” They are also required to offer sinkhole damage coverage as an option, and it generally appears in a rider that comes at an additional cost. The insurance law defines catastrophic ground cover collapse in a different way than it defines a sinkhole.
Catastrophic Ground Cover Collapse
By Florida law, four conditions must be met for Florida homeowner’s insurance to cover damage (building and contents) from catastrophic ground cover collapse:
The sinking of the top layer of soil must occur abruptly.
A depression in the ground cover must be clearly visible without the aid of instruments.
There must be structural damage to the home, including the foundation itself.
A government agency must condemn and evacuate the structure.
Settling or cracking of a structure does not automatically trigger coverage for catastrophic ground cover collapse.
Damage from a sinkhole that meets all the above conditions should be included in coverage for a catastrophic ground cover collapse. Damage from a sinkhole that does not meet the above conditions will not be covered, unless sinkhole coverage has been purchased separately.
Changes in Florida Insurance Law
In most states, coverage for home damage due to earth movement is not required. Only Tennessee and Florida require certain kinds of coverage for earth movement. Until 2007, sinkhole insurance coverage in Florida was very broad. In 2007, the Florida legislature passed Florida Statute 627.706, which requires insurance companies to provide all homeowners with coverage only for catastrophic ground cover collapse. Broader coverage for less severe damage from sinkholes was changed to an optional coverage (which would cost more).
Sinkhole claims tripled between 2007 and 2011, according to the Tampa Bay Times. There was not a clearly defined threshold for what structural damage was covered. Insurance companies faced major losses. In 2011, the legislature passed Florida Senate Bill 408, narrowing the scope of qualifying damage. Also, money paid for claims then had to be used to repair the property. Other provisions under the current law also include the following:
- A sinkhole loss must include structural damage that includes the foundation.
- Structural damage must involve foundation movement that exceeds an acceptable variance in the building code, and it must cause the structural systems to be unable to support the loads they were designed for.
- There is a 2-year limit for filing sinkhole damage claims.
- Homeowners who accept a rebate from a contractor after filing a claim risk having their sinkhole insurance voided and having to repay the rebate.
Time limits for testing by the policyholder, signing of repair contracts, and repair completion were established.
What the Law Says About Sinkhole Insurance
Insurance law in Florida states that a sinkhole claim must be paid only if there is structural damage that includes damage to the foundation, and it must exceed a certain variance in the building code. It must also cause the structural system to be unable to support the load or weight it was designed to support. A sinkhole claim must be filed within two years of the damage. There are other time limits on the steps of the process.
The Insurer’s Initial Responsibilities
An insurer has certain obligations to a homeowner that holds a policy and reports they may have a loss due to sinkhole activity.
- The insurance company must inspect the premises to determine if there is structural damage that might be caused by a sinkhole.
- If there is structural damage, the insurance company must hire and pay for a professional engineer or professional geologist to test the site and determine the cause of structural damage “within a reasonable professional probability.” If the loss is covered, the insurance company must issue a report to the homeowner.
- The insurer must provide the homeowner with a disclosure of what caused the damage (if determined) and what circumstances require the insurance company to hire a professional to make recommendations regarding stabilizing the land and building and repairing the foundation.
- The insurer must also disclose the homeowner’s right to request professional testing, at what points the homeowner has that right, and the circumstances when the homeowner must incur the costs for professional testing.
The Homeowner’s Right to Geological Testing
If the insurance company decides there is no loss due to a sinkhole, they may deny the claim. If the policyholder has sinkhole coverage, and the claim is denied, then the policyholder may demand testing, if they do so in writing within 60 days of the denial of the claim. In this case, the homeowner pays 50% of the lesser of the cost of the professional testing or $2,500. The insurer reimburses the homeowner if the testing shows that there is a sinkhole loss.
The Insurer’s Responsibility in the Event of a Sinkhole Loss
If a sinkhole loss is confirmed, the insurance company must notify the policyholder, stabilize land and building, and repair the foundation according to the recommendations of the professional engineer within the terms of the policy. If other repairs to the home or contents are guaranteed in the policy, they must be provided. If the recommended repairs cannot be completed within the limits of the policy, then the insurance company must complete the repairs or simply pay up to the limits of the policy.
The Responsibilities of the Homeowner
If the policyholder does not contract with a stabilization company to make the repairs recommended by the engineer, then the insurance company only has to pay for the repairs to the building and not the repairs underneath the building, such as grouting or underpinning.
Because further damage could result if stabilization and foundation repairs are not commenced quickly, the policyholder must contract for the repairs within 90 days after the loss is confirmed and the homeowner is notified. If there is a dispute, a “neutral evaluation process” could interrupt this 90 day clock.
Payment of the Sinkhole Claim
The insurance company must pay as the sinkhole stabilization and foundation repair are completed. If it’s determined in the process that the work cannot be completed within the policy limits, then the insurer must either complete the repair or pay the homeowner the amount of the policy limits without subtracting the cost of work already performed.
Timing of Soil Stabilization and Structural Repairs
The repair work must be completed within 12 months after the homeowner enters into a contract for repairs, unless the homeowner and insurer mutually agree, or if the claim is subject to some sort of dispute resolution process.
Illegality of Rebates
If the homeowner accepts a rebate from a repair company, coverage of the policy is voided, and the amount of the rebate must be paid to the insurer. If the company performing the repairs offers a rebate, it is considered insurance fraud punishable as a third degree felony. A rebate is “remuneration, payment, gift, discount, or transfer of any item of value to the policyholder “ by the repair company as “an incentive or inducement.”
If you file sinkhole claims, the insurer can only refuse to renew your homeowner’s policy if the payment of sinkhole claims equals or exceeds the limits of the policy or if you do not repair the structure according to the engineer’s recommendations.
To read the law for yourself, follow this link.
A confirmed sinkhole is one that has been verified by a geologist or an engineer. This is important, because in Florida, the opinion of a geologist is an important factor in determining the obligation of the sinkhole insurer to pay your claim.
Analysis of sinkhole damage to a home requires the expertise of a geologist in understanding what, from a geological perspective, is causing unstable soil. The goal is to understand what layers and formations of soil, rock, sand, limestone, clay, water, etc. exist underneath your home and to what degree they provide, or fail to provide, solid support for the weight of your home. This is difficult, because no one can see what is below the soil on which your home rests. It requires knowledge of the geological characteristics of the general area as well as expertise in the testing protocols and equipment that can reveal exactly what is happening on your property.
A structural engineer also has expertise that is critical in understanding the impact of geological variables on your home. A structural engineer understands the materials used in construction (e.g., wood, masonry, concrete, steel, etc.) He or she also understands the structural systems of beams, columns, and other members that give support to a building. The engineer is able to calculate the loads—the weight and the other forces that act upon the structure—to determine the foundation support required.
To confirm sinkhole damage requires both geological and engineering experts.
Experts Determine Geologic Cause of Structural Damage
Two areas of expertise are needed to determine whether sinkhole activity is the cause of structural damage and how it can be repaired: Geology/Geotechnical Engineering and Structural Engineering.
Because there is so much variability in local geological formations, there is no standardized set of testing and analysis steps, and professional judgment is important. However, there are generalized steps, processes and tools that help to inform professional judgment.
Initial Data Gathering
The first step is to collect background data on the site, including the area’s geomorphology, or types of layers and formations. Also helpful is information on elevation, topography, and drainage. Soil conditions in the area and the area’s history of sinkholes should be part of the background information. Aerial photographs of land features may be telling. Recent rainfall events should be considered. Maps and elevations of nearby water bodies are potential factors. Finally, background data should include the construction date of the house and of any additions or modifications should be noted.
Preliminary Site Inspection
It’s important for professionals to visit the site of structural damage and discuss with the owner or resident nature and timing of damage to the structure and any noteworthy facts about the property, e.g., wells, buried debris, removed tree stumps, etc. The land itself should be inspected for any suspicious surface features, slopes, walls, water bodies, and utilities. Data should be collected concerning widths of cracks, stressed vegetation, soil erosion, leaning walls or fences, location of septic tank, orientation of gutters and downspouts, etc. New construction in the area should be noted. Photographs should be taken. It should also be determined to what degree access is available to conduct geophysical and geotechnical tests.
Geophysical Site Characterization
With background data and a preliminary site inspection, it should be possible to develop a hypothesis of subsurface geology and then undertake appropriate geophysical investigations to confirm or modify the characterization. Among the tests that may be used are the following:
- Ground Penetrating Radar, using radar pulses to image the subsurface and clarify shallow soil and rock conditions.
- Profiling of Electrical Resistivity, measuring resistance of the soil to electrical current to identify the different materials that might be present.
- Micro Gravity Surveys, measuring changes in earth’s gravity as small as one part in 1 billion to aid in characterizing geological formations.
- Magnetometer Testing and other testing to determine where utilities may be buried.
- Surface Wave Measurements, using vibrations to characterize subsurface features.
Floor Mapping is the use of precise tools to determine where a structure’s floor is depressed or elevated beyond tolerances specified in building codes. Through these tests, a contour map of the structure’s floor may reveal insights about what is happening beneath the structure.
Subsurface Geological Testing
Experts may conduct standardized tests of soil penetration to determine soil characteristics. Samples from boring into the ground may be collected and analyzed. Cone penetration tests push a pipe with a cone on the tip into the ground at a controlled rate to delineate soil layers and materials. A number of different subsurface tests may be conducted.
Soil samples may be collected and tested for moisture content, gradation or grain size through laboratory testing.
The affected structure will be inspected for deterioration, modifications, and construction defects.
The Final Report
The final report that clarifies whether structural damage is caused by a sinkhole should include the expert opinion on what the cause of the damage is within a reasonable degree of probability. It should include all of the evidence used to arrive at the expert opinion. It should include the raw, uninterpreted data in the appendices of the report. All photographs, notes, and other documents, as well as samples collected at the site, should be retained by the professional for an appropriate time.
For more information, refer to this report. http://www.dep.state.fl.us/geology/publications/sp/sp57d.pdf