Sunday, April 12, 2009

Denver Steeply Dipping Bedrock REVISITED

Facts about Denver's Steeply Dipping Bedrock Hazard Area is something most home buyers, current home owners, Realtors®, home inspectors and builders know little about; but should. A previous blog discussing various aspects of the Dipping Bedrock Hazard Area provide insight to problems home owners may experience if their home was built within the affected areas.

I was recently contacted by one home inspector who happens to be an expert on the subject. Joseph Wujek, M. A., owner of Advanced Building Consultants, LLC was kind enough to pass along a very informative fact sheet about the Denver area Slidding Dipping Bedrock Hazard Area.
Some of the key points for metro Denver area home buyers to know are:
* Sedimentary deposits formed the bedrock layers 80 million years ago.
* As the Rocky Mountains push through the ancient horizontal layers of bedding planes of Pierre Shale they caused the bedrock layers to stand nearly vertical in some areas of Jefferson, Douglas and El Paso Counties. These areas are more commonly know as Steeply Dipping Bedrock.
* When moisture is added to these tilted layers they may slide with the movement in severe.cases causing structural failure of building foundations. Ground movement has been as much as two feet and extending hundreds of feet.
* Future movement can continue for decades even no prior movement has occured for decades
* Slipping dipping bedrock destruction at a particular site can only be determined with extensive geological and geotechnical investigation.
* Structures such as homes should not be built on some of the Slipping Dipping Bedrock areas.

* Differential heaving (uneven lifting) of the home, or nearby sidewalks, driveways, and streets.
* Uneven sloping of patios, porches, and floors.
* Large cracks around windows and doors, and in foundation walls.
* Doors and windows that bind.
* Evidence of repairs of severe cracks in interior drywall walls and ceilings.

Full-size copies of Slipping Bedrock Hazard Area map can be purchased by calling
The Jefferson County Planning and Zoning Department at 303-271-8700.

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