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A blog with answers
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HOME INSPECTION
and HOME MAINTENANCE

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Welcome to our blog!
We want you to be an informed homebuyer, and each blog post is a question that we have answered for our friends and customers over the years. Hope they help you make a good choice for your next home.

    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 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. It is the red area in the Alachua County map above.

   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.

   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 homeowners protect themselves against buying a house over a sinkhole?”

   To read more about clay soil and sinkholes, here’s a link to an April 14th, 2007, article in the Gainesville Sun, that covers the subject thoroughly:

http://www.gainesville.com/article/20070414/SUNFRONT/704140371

   Also, here’s a recent article about a sinkhole that appeared overnight in the backyard of a Jonesville home:

http://www.gainesville.com/article/20120512/ARTICLES/120519871?tc=cr

    Click on the link below for an Alachua County map locating known sinkholes as of 2008:

AlachuaSinkholeMap.pdf

   And a “Sinkhole Facts” sheet from Alachua County:

AlachuaSinkholeFacts.pdf


While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© - McGarry and Madsen Inspection.

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