A large number of homeowners (~ 1,200) in the Town of Amherst have reported foundation –related damages (bowing, cracking) that result from lateral pressure and differential settlement. There are multiple causative factors that include soil conditions, local hydrology, and residential design and construction practices. The Corps began a cooperative Section 22 study with the Town in 2004 to determine the causes and potential solutions to the problem. The results of study were presented to the Town Board and public in April-May 2005. The final report is posted at the Town of Amherst's website. Copies of the report (CD and paper) can be obtained through the Amherst Building Department.

Project Schedule

• Final Report posted online November 2005

Accomplishments

The Town of Amherst Soils and Foundation Stability tasks included:

• Performed an exhaustive literature review,

• Input geologic data from more than 400 boring logs,

• Analyzed the Town’s foundation repair permit and complaints database,

• Used the Town’s GIS to examine geographic patterns of soils and foundation-related problems,

• Inspected more than 40 homes,

• Conducted a phone survey with 70 homeowners,

• Sampled soils from approximately 30 sites across Amherst, and

• Continuously communicated our findings to numerous technical groups, the press, and Town officials.

Acknowledgement

We graciously thank those homeowners who both volunteered information and/or participated in the study. We also thank members of the Project Delivery Team that included federal, state, town, and neighbor representatives. We owe special thanks to the congressional and state representatives that have provided funding and encouragement for this study.

Grants

Regrettably, the Corps does not have an authority to provide funds for repairing private homes. There is a task force and nonprofit agency that is pursuing potential grant sources. We are providing technical answers to these groups but are not are not involved in their selection process.

Homeowners

Guides:

(1) Noe, D.C., Jochim, C.L., and Rogers, W.P. (1997). A Guide to Swelling Soils for Colorado Homebuyers and Homeowners, Special Publication 43, Colorado Geological Survey Department of Natural Resources. Call (303) 866-4762. See: http://dnr.state.co.us/geostore/default.aspx

(2) Freeman, T.J., Littlejohn, G.S. and Driscoll, R.M.C. (1994). Has your House got Cracks?; A Guide to Subsidence and Heave of Buildings on Clay, Thomas Telford Services Ltd, London, England. See: https://www.asce.org/bookstore/book.cfm?book=2722

(3) ASCE, American Society of Civil Engineers (1995). So Your Home is Built on Expansive Soils, ASCE, New York. See: https://www.asce.org/bookstore/book.cfm?book=3591

Photos

Lateral pressure causing typical 45 degree stair-step crack in block basement wall.	Lateral pressure causing vertical mid-span crack in basement wall.
Lateral pressure causing top of basement wall to bow inward 9 inches (pilasters failed to brace wall).	Unconnected downspout and drainage toward house lead to hydrostatic pressure on basement wall.
Sampling of stiff stratum that underlies many Amherst footings. These soils are expansive and shrink and swell with moisture changes.	Sump pit with tree roots penetrating into perimeter drain system. This creates potential for uneven moisture under the house.
Foundation construction illustrating potential for developing uneven moisture conditions during and after house construction.	Excavation of soft stratum soils in north Amherst.

Reports

Amherst Soils and Residential Foundation Study Final Report (October 2005) Entire Document (large file).

For a smaller file, the final report is posted in sections at the Town of Amherst's website. Copies of the report can be obtained through the Amherst Building Department.

Links

• Town of Amherst Building Department
  
  

• Town of Amherst Soils/Foundation Information

For further information, contact:

Phil Berkeley, Senior Planner, Project Manager

Email: Phil Berkeley

(716) 879-4145