A Resolution Establishing an Expansive Soil Testing Policy


            WHEREAS, the Virginia Uniform Statewide Building Code (USBC) requires Virginia localities having 20% and greater moderate and high shrink/swell potential to implement an expansive soil test policy; and


            WHEREAS, 20% or more of Fauquier County has soils of moderate and high shrink/swell potential; and


            WHEREAS, failure to design and build structures affected by shrink/swell soils can result in great damage to such structures; and


            WHEREAS, the following policy is consistent with State law and is in the interest of public health, safety, and welfare, of Fauquier County residents and businesses; now, therefore, be it


            RESOLVED by the Fauquier County Board of Supervisors this 8th day of September 2005, that the Board of Supervisors does hereby adopt the following Expansive Soil Test Policy and directs the County Building Official and other County employees, as appropriate, to enforce the Expansive Soil Test Policy:


General Requirements:


Building permits must include soil test data for all construction sites requiring footers that are proposed to be built on soil types having a shrink/swell potential of moderate or higher or within 1000 feet of a soil map unit with shrink/swell potential of moderate or higher, based on the Fauquier County Soil Survey, as provided on the Fauquier County GIS Maps Online, and The Interpretative Guide to the Soils of Fauquier County, as provided on the Fauquier County website.


Soil testing will also be required if indications of shrink/swell soils are found by representatives of the Building Official or a third party inspection agency during routine inspections.


When soils are determined to be expansive, foundation design shall be in accordance with the current edition of the USBC.




  1. Additions to one- and two-family dwellings or slab-on-grade accessory structures and decks where there is no indication of shrink/swell condition for the area. A signed affidavit shall be submitted by the property owner or other approved representative.


  1. The permit applicant provides the Building Official with plans designed, sealed and signed by a Virginia licensed engineer or architect, along with a signed, sealed and dated letter from the professional, stating that soils with a very high shrink/swell potential were assumed present at the site and that the foundations of the building are designed to overcome the limitations presented by this soil condition. The letter and the plans shall accompany the building permit application.


  1. A Final Soil Report, for an approved residential subdivision, is submitted by a Virginia Certified Professional Soil Scientist, as required by Fauquier County Subdivision Ordinance (Section 9-5C), concludes that soils on the proposed dwelling construction lots have below moderate shrink/swell potential.


Authorized Persons to Perform Soil Test:


Soil testing or evaluation will be performed by a licensed professional, such as a Virginia licensed Professional Engineer, Certified Professional Soil Scientist, or a Certified Professional Geologist who is accredited with the Virginia Department of Professional and Occupational Regulation.


Soil Sampling Requirements:


When required, soil testing must be site specific and the testing report submitted to the Building Official prior to issuance of the building permit for the proposed construction.


A minimum of two borings shall be provided at opposite corners of the proposed structure to a minimum of 5 feet or to auger refusal on non-shrink/swell geologic strata. For structures with basements, the borings must extend to a minimum depth of 24 inches below the basement footing, as determined by the building code or to auger refusal on non-shrink/swell geologic strata. Additional borings may be required based upon proposed construction or soil encountered or recommendations of the accredited professional.


A sample will be taken from each site from between the ground surface and 24 inches below the proposed footer bottom. The sample should represent the layer within this zone that exhibits the greatest shrink/swell potential. The sample shall be submitted to a laboratory for testing.


Laboratory Testing Requirements:


The following laboratory tests, based on USBC R403.1.8.1, shall be performed to determine if a soil is expansive:


1.      Plasticity Index (PI), in accordance with ASTM D 4318; and

2.      No. 200 sieve analysis, in accordance with ASTM D 422; and

3.      Particle size, in accordance with ASTM D 422; or

4.      Expansive Index, in accordance with UBC Standard 18-2 or SBCCI SSTD 7.


(Tests 1, 2, and 3 are not required if the test in item 4 is conducted.)


Soil Testing Report Requirements:


  1. A drawing to scale showing all boring locations


  1. Detailed soil profile descriptions.  These descriptions shall include any evidence of free water, redoximorphic features indicating a seasonal high water table, and expansive activity.


      3.   The stamp or seal and signature of the accredited professional providing the soils           evaluation and/or test information, including full address, must be placed on all             reports


; and, be it


RESOLVED FURTHER, That this policy becomes effective three weeks after adoption.