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

Friday, October 19, 2018

While sinkholes are not the big problem in Alachua County that they are in Florida counties farther south—such as in Pinellas, Hernando, and Hillsborough—they do  happen occasionally throughout most of Florida. 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. It’s a state park, and the stairs to the bottom, shown below, are an enduring tourist attraction. Plus, many of the lakes in the area were formed by sinkholes.

    There are three major types of sinkholes: 1) solution sinkholes, 2) cover subsidence sinkholes, and 3) cover collapse sinkholes. The first two types sink slowly over time. It’s the cover collapse sinkholes, which usually fall down abruptly and dramatically, that are on the evening TV news. To learn more about the different categories of sinkholes, see our blog post What causes sinkholes?

  But the more prevalent underground defect in some North and Central Florida areas 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 “Hawthorne Formation,” for example, runs through the middle of Alachua County, roughly north-south along I-75 and east-west along Newberry Road. The cross-section below is from a USDA soil survey of Alachua County from 1985.


   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. Go to our blog post How can I tell whether my house foundation problems are caused by a sinkhole or expansive clay soil? for more on this.

   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 get a better understanding of sinkhole insurance coverage, see our blog post How can homebuyers protect themselves against buying a house over a sinkhole? 

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

Here’s links to a collection of our other blog posts about SINKHOLES:

Why do so many more sinkholes open up after a hurricane?

What can I do if the insurance company denies my claim for a sinkhole loss in Florida?

What is a chimney sinkhole? 

What are the warning signs of a sinkhole? 

What causes sinkholes? 

 
• How does a repaired sink hole under a house affect its market value?

• Where are sinkholes most likely to occur in Florida?  

Are there sinkholes in The Villages, Florida?

• Are sinkholes happening more often? 

What are the basic facts about sinkholes? 
  
• Does homeowners insurance in Florida include coverage for sinkhole damage? 

Should I be concerned about an old sinkhole on a property?

• Should I be concerned about my house if a sinkhole opens in my neighbor's yard? 

What are the Florida law regarding sinkhole insurance?

Can a home inspector determine if there are any sinkholes on a property?

Is it safe to buy a house with sinkhole foundation repair? 

   Visit our SINKHOLES page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

Water Heaters

Water Heater Age

Wells

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests

Sinkholes

Stairs

When It First

Became Code

"Should I Buy A..."

Park Model Homes

Site

Shingle Roofs

Safety

Stucco

Remodeling

Wind Mitigation Form

Roof and Attic

"Does A Home

Inspector...?"

Pool and Spa

"What Is The Difference Between..."

Radon

Brick

Plumbing

Concrete and

Concrete Block

Metal Roofs

Foundations

Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants

Condominiums

Older and

Historic Houses

Crawl Spaces

Mobile/Manufactured Homes

Building Permits

Life Expectancy

Clay Soil

Insurance

Floors

Insulation

Toilets

Exterior Walls & Structures

Generators

Common Problems

HUD-Code for

Mobile Homes

Garages and Carports

Flat (Low Slope) Roofs

Electrical Panels

Sprinkler Systems

Electrical Receptacle Outlets

4-Point Inspections

Hurricane Resistance

Frequently Asked Questions (FAQ)

Home Inspection

Heating and Air Conditioning

Building Codes

Fireplaces and Chimneys

Inspector Licensing

& Standards

Energy Efficiency

Washers and Dryers

Electrical

Kitchens

Doors and Windows

(placeholder)

Cracks

Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps

Appliances

Smoke & CO Alarms

Aging in Place

Top 5 results given instantly.

Click on magnifying glass

for all search results.

Bathrooms

Lighting

AFCI, CAFCI,

DFCI, & GFCI

Sinks

Air Conditioner & Furnace Age/Size

Attics

Electrical Switches

Siding

Search

This

Site

Water Intrusion

Electrical - Old

and Obsolete

(placeholder)

Foundation Certifications

Tiny Houses

How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactured and modular homes

About Us