What is my chance of buying a home over a sinkhole?

Home Inspector with McGarry and Madsen Home Inspection

While sinkholes are not the big problem in Alachua County that they are in Florida counties farther south--such as Pinellas, Hernando, and Hillsborough--they do  happen here occasionally. The limestone underlayment of much of this area, called “karst,” is the root of the problem. Deterioration of the underground karst due to percolation of acidic rainwater through the soil causes voids to form, which collapse slowly, or sometimes abruptly, like in the dramatic newspaper photos of homes swallowed up overnight by a sinkhole.
   The “Devil’s Millhopper” in northwest Gainesville is the largest sinkhole in Florida, and the state park’s stairs to the bottom is an enduring tourist attraction. Plus, many of the lakes in the area were formed by sinkholes.
   But the more prevalent underground defect in this area is clay soil. The elasticity of clay causes it to shrink during dry spells, then swell during seasons with heavy rains. The swell/shrink cycle causes the ground under a home built over a layer of clay soil to heave up and down in seasons that are extra wet or dry. A hilly band of clay soil that geologists have labeled the “Hawthorn Formation” runs through the middle of Alachua County, roughly north-south along I-75 and east-west along Newberry Road.
   Determining whether structural cracks in a home are due to sinkhole activity, clay soil, or erosion, is complicated. And engineering experts sometimes reach different conclusions about the cause of a structural problem when examining the same home.
   But the determination of what’s causing a home to start cracking apart can a make a big difference as far as getting your homeowner’s insurance company to pay for repairs. Clay soil is considered an existing condition and is not covered, while sinkholes are. Or, at least, sinkholes can be covered, if you pay additional for it when the policy is written. They are typically excluded in standard policies nowadays.
   To read more about clay soil and sinkholes, and view a map of the Hawthorn Formation, here’s a link to an April 14th, 2007, article in the Gainesville Sun, that covers the subject thoroughly:


   Sinkhole claims have been on the rise over the past few years around the state, however, and here’s a recent Gainesville Sun commentary about the proliferation of insurance claims:



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Robert L. Brown
www.mrbrownsellsgr.com - Grand Rapids, MI
Grand Rapids Real Estate Bellabay Realty, West Michigan

How is the Broward county area for sinkholes? I have friends in the area.

Oct 08, 2011 07:56 PM #2
Greg Madsen and Richard McGarry
McGarry and Madsen Home Inspection - Gainesville, FL

Good question, Robert. Typically, South Florida has less of a sinkhole problem. But, I don't have any current data to back that up.

Oct 08, 2011 08:16 PM #3
Jackie Connelly-Fornuff
Douglas Elliman Real Estate in Babylon NY - Babylon, NY
"Moving at The Speed of YOU!"

Hi Greg, I never knew about sinkholes in Florida let alone Gainesville, FLA. That is what's great about AR. You always learn something new.

Oct 08, 2011 09:53 PM #4
Paula McDonald
Chevaux Group, PLLC - The Woodlands, TX
CHEVAUX Group ~ The Woodlands, TX 936-203-0279
This would never be a good situation for anyone. Here in the Houston area we see them from time to time.
Oct 08, 2011 10:42 PM #5
Kathleen Daniels
KD Realty - 408.972.1822 - San Jose, CA
San Jose Homes for Sale - Probate Specialist

Just reading the title my response is:  The risk of my home sinking!  I would not purchase a home built over a sinkhole. 

Oct 08, 2011 10:46 PM #6
Richard Weisser
Better Homes and Gardens Real Estate Metro Brokers - Newnan, GA
Richard Weisser Coweta Newnan Homes for Sale


That's something we don't think about in our area. It's pretty scary.

Oct 08, 2011 11:59 PM #7
Donald Reich
Prudential Centennial - New Rochelle, NY

Great post!  I think that sink holes are a big red flag.    

Oct 09, 2011 12:02 AM #8
Lloyd Binen
Certified Realty Services - Saratoga, CA
Silicon Valley Realtor since 1976; 408-373-4411

Can the space created by a sink hole be used as a basement?  Sink holes are a very weird phenomena; thanks for your explanation.

Oct 09, 2011 01:39 AM #9
Jon Quist
Tucson's BUYERS ONLY Realtor since 1996

We just had a major sinkhole here last week. Of course someone excavating hit a major water line , thusly the sinkhole.

Ground here is REALLY hard. As testament to just how hard the ground is here, we have AMARG, an aircraft storage group that takes care of more than 4,400 aircraft, which would make it the second largest air force in the world. The planes are parked not on a tarmac, but the dirt! Hard dirt! 

Oct 09, 2011 01:57 AM #10
Evelyn Kennedy
Gallagher & Lindsey, Alameda, California - Alameda, CA
Alameda, Real Estate, Alameda, CA

Greg and Richard:

Interesting post about sinkholes.  I haven't heard about sinkholes in my city, but there have been sinkholes in areas nearby.  They don't seem to be a big problem.

Oct 09, 2011 03:20 AM #11
Marc Swartz, CPA, CA, Real Estate Broker
RE/MAX Vision Realty Inc., Brokerage, Direct: (416) 737-9800, Office: (416) 321-2228 - Toronto, ON
Toronto, Durham & York Regions, Ontario, Canada

Hi Greg and Richard - We just had a 30 feett wide and 6 to 10 feet sinkhole by a major road in my area in the past week or two.  The sinkhole was caused by a broken watermain.

Oct 09, 2011 05:20 AM #12
Phil Leng
Keller Williams Eastside Market Center - Kirkland, WA
Phil Leng Team - Residential Real Estate Experts &
Hi Greg and Richard, Interesting post. Certainly something that someone with expertise needs to advise on. The phon e call none of us want to get. "The house you helped me buy just got swallowed up!" Phil
Oct 09, 2011 05:50 AM #13
Fernando Herboso - Broker for Maxus Realty Group
Maxus Realty Group - Broker 301-246-0001 - Gaithersburg, MD
301-246-0001 Serving Maryland, DC and Northern VA




A great example that expertise is needed in any area of real estate. .great job guys. .

I used to be married to a sink hole. .I barely made it out alive. .lost all my investment homes and an apartment building. . never seen them back!!

Oct 09, 2011 06:25 AM #14
Mike & Eve Alexander
Buyers Broker of Florida - Windermere, FL
Exclusively Representing ONLY Orlando Home Buyers

Lets not forget that some sinkholes are caused by builders building a community over a trash dump...that eventually settles...


Eve in Orlando

Oct 09, 2011 06:45 AM #15
Joy Daniels
Joy Daniels Real Estate Group, Ltd. - Harrisburg, PA

Buy SINK HOLE INSURANCE!  If you live anywhere near an area prone to sink holes - spend the little bit extra each year to be covered. 

Oct 09, 2011 08:44 AM #16
Barbara-Jo Roberts Berberi, MA, TRC - Greater Clearwater Florida Residential Real Estate Professional
Charles Rutenberg Realty - Palm Harbor, FL
Palm Harbor, Dunedin, Clearwater, Safety Harbor

Sinkhole insurance is getting harder and harder to obtain and once there has been a settlement issue many companies will no longer insure the home. My suggestion to clients is to WALK if the listing has had ANY sinkhole activity. I believe on being SAFE over sorry later.....

Oct 09, 2011 09:01 AM #17
Tropic Shores Realty - Ich spreche Deutsch! - Spring Hill, FL
Florida Waterfront and Country Club Living

Good topic.  It's important to remember that not every crack is automatically a sinkhole even though some companies would like homeowners to believe that.  I've talked to people who've made sinkhole claims for something that happened in the backyard where many years prior a big tree had been removed.  I've seen engineering reports that essentially said something to the effect of "foundation repairs not required but if you feel better about it, we can pump a few cubic tons of grout under it".  Most importantly, even without added sinkhole coverage, homeowners are still covered in the event of "catastrophic" loss. 

Oct 09, 2011 09:03 AM #18
Frank Laisch
Stewart Title Company - Tampa, FL
"The Insurance Guy"

great post, Silvia'a comment is so true. "even without added sinkhole coverage, homeowners are still covered in the event of "catastrophic" loss"  the Fraud claim and frivolous lawsuits have been killing Florida insurance for the last few years which prompted new insurance laws this year...

Oct 09, 2011 09:52 AM #19
Michael Setunsky
Woodbridge, VA
Your Commercial Real Estate Link to Northern VA

Greg and Richard, I wasn't aware of the problems with sink holes in Florida. Good information!

Oct 09, 2011 10:02 AM #20
Jack O'Neal
Solutions Real Estate - Phoenix, AZ
High Touch High Tech

Wasn't this a bad scifi moving? This is a great post in Arizona, we have problems with expansive soil and foundation cracks, but this is totally new to me. A good reason you do not sell outside your geographical area of expertise.

Oct 09, 2011 05:11 PM #21
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