I mostly hear about sinkhole claims in Pasco and Hernando County. I live in the Miami, Dade County area and have noticed some cracking. But I’ve heard that because there’s not limestone in this area, the cracking can’t be the result of sinkhole activity. Is that true?
I believe what you’re alluding to is the fact that people commonly think of sinkholes as dissolved limestone. In fact, the statutes on sinkhole activity, as defined by the State of Florida, do not necessarily limit sinkhole activity to only the dissolution of limestone. (Learn more about Florida’s legal definition of sinkhole.) The definitions mention other rock and underlying strata. It is true that many parts of South Florida and the Dade County or Miami areas “The creation of new primary schools districts is an excellent example of how the borough council continues to invest in our schools districts and their pupils. do no sit on a true layer of limestone but do sit on other forms of rock, which we believe, if suffering from dissolution, satisfy the definition of a sinkhole.
In fact, the primary reason damage due to sinkhole activity is covered by insurance relates to a large, cover collapse sinkhole that occurred in Winter Park, outside of Orlando. Additionally, of all the clients we currently represent, the largest increase in claims has been in the “less expected” areas, such as Ocala (Marion County) and South Florida. There may not be a scientific explanation for this; it could be that there’s just an increased awareness by the property owners.
The focus should be less on whether your cracking could or couldn’t be attributed to sinkhole activity and more on getting whatever is causing the damage resolved. Under Florida law, an insurance company must not only determine whether it is a sinkhole, but also whether or not there is an alternative cause for the damage (e.g. organic soils, clayey soils, construction defects). You may find yourself in a situation where you are presenting minimal evidence of sinkhole activity, but the claim has to be paid because the engineering firm cannot determine the cause of the damage with any reasonable degree of specificity.
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My insurance company just sent me the report following my sinkhole investigation, along with a letter that really tells me nothing. When I read this, what should I be looking for?
Reports prepared by geologists and geotechnical engineers following the investigation of a sinkhole claim can be very difficult to understand. They contain a voluminous amount of general information, much of which is of a highly technical nature. However, there are certain issues to look for in reviewing a sinkhole investigation report prepared by your insurance company’s consultants.
The Florida Statues require professional engineers and professional geologists performing sinkhole investigations to “perform such tests as sufficient, in their professional opinion, to determine the presence or absence of sinkhole loss or other cause of damage within reasonable professional probability…”
Engineers and geologists performing sinkhole investigations typically perform tests including geophysical surveys, such as ground penetrating radar and electrical resistivity. These studies look for odd areas (called “anomalies”), which may or may not be sinkhole activity. At a minimum, the engineer or geologist should study these further.
There are several indicators of sinkhole activity, which may be uncovered by an SPT boring. First, the SPT borings may indicate the presence of subsurface voids or cavities (usually indicated in the boring logs as “weight-of-rod” or “weight-of-hammer” conditions). Such voids or cavities often indicate sinkhole activity. Second, there is often a “loss of circulation,” which is a movement of fluid in the drill rig showing a void. There are also more subjective indicators, which relate to the comparative density of the soil above and below various depths in the boring (very technical stuff). If you find any of these facts in a sinkhole investigation report prepared by your insurance company’s experts or have any other questions concerning the report, you should have the report reviewed by a competent professional.
Read my tips on filing a sinkhole claim.
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Is a sinkhole just a hole in a rock?
I found a really good site from the Department of Environmental Protection in Pennsylvania on sinkholes and what causes sinkholes to form. I especially found the portion on “what is a sinkhole” or “what is sinkhole activity” well-written and worthy of quoting here:
A common misunderstanding is to think that a sinkhole is the hole in the rock. Actually, the sinkhole is what we see on the ground surface because of the hole in the rock below. The space in the rock (known as a void, solution cavity or cave) takes hundreds or thousands of years to form. Then soil from above can move into the void in rock. If the soil is sticky, a void can form within the soil. As more soil washes down (over years or maybe just days), the void space moves toward the surface until it can’t hold together anymore. When it collapses (or subsides), you see the sinkhole on the surface. Often, you can only see soil in the hole and not the actual hole in the rock itself because the rock is too far below.
Pennsylvania sees a lot of sinkhole activity due to the amount of mining activity taking place there, much like what has happened in Polk County. The subsurface is very similar to our counties in Hernando, Pinellas, and Pasco, with a shallow limestone impacted by the movement of what over the limestone.
Read the full article.
Learn more about what causes sinkholes.
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What makes a sinkhole?
Sinkholes are one of the only causes of damage actually defined by Florida sinkhole laws. One of the reasons there had to be a legal definition, is that otherwise, you could ask two different geologists the question “what is a sinkhole” and you’d get two different answers.
This can cause a variety of concerns for you, your insurance company, and the law. Therefore, it’s important to know that the difference between a sinkhole and simple property damage is what caused it.
What causes sinkholes to form
A sinkhole loss is associated with the dissolution of limestone or the calcium carbonate rock that lies beneath most of Florida. Calcium carbonate dissolves when it comes in contact with water because the pH level of water in Florida is acidic.
After a while, portions of the underlying rock form holes as the water washes over the stone. When this happens, soil can move or “ravel” into the holes. This results in the surface moving, even if it does not actually create a “hole” as you mentioned.
How to know the difference
So you may be right, but so may your neighbor. You can have sinkhole activity, even when there is no giant sinkhole in your yard. The only way to know is to either hire an engineering firm or demand that your insurance company do so.
Proceed with caution, as you might find yourself in an argument with your insurance company. Whether or not they feel like a sinkhole inspection is necessary can make a big difference – they’re expensive, and you probably don’t want to foot the bill yourself.
If you find yourself in this situation you may also consider contacting an attorney to see what you can do to get leverage in this situation. Sinkhole claims involve some fine lines, to tread with care.