Shenandoah County Soil Testing Policy for Residential Construction

As of January 1, 1998 and amended October 1, 2004, all new residential construction, built under International Residential Code for One and Two Family Dwelling, Section R403.1.8, prior to the issuance of a building permit or prior to footing inspection. The soil scientist shall classify the soil(s) according to the Unified Soil Classification System. All findings and recommendations shall be placed in writing to the owner and a copy supplied to this office. The cost of the soil investigation shall be at the expense of the owner.

A soil test may be performed using one of the following methods:

1. A site investigation of the proposed house location by evaluating a sample using the ‘Hand Test’ method. The geology and topography, and the environmental and climatic conditions shall be considered in the evaluation.
2. Laboratory testing of a soil sample from the proposed site location which measures different characteristics of the soil. Atterberg limits is a common indicator for the potential of expansive soils and is an acceptable method of soil testing for liquid and plastic limits.

Note: Wash or bucket samples are not acceptable. A standard test boring methods to obtain either split-spoon or thin-wall sample is required.

In lieu of a soil test, a specific site design may be provided by a registered Virginia Architect, Engineer, or other qualified persons as approved by the Code Official. The geology and topography, and the environmental and climatic conditions shall be considered in the design. All the designs must be in compliance with the Virginia Uniform Statewide Building Code (USBC) and meet the minimum requirements of the IRC for One or Two Family Dwellings.

The designer may use the Soil Survey of Shenandoah County, Virginia as a reference for assisting in the determination of potential shrink/swell soils on the proposed building site. Any field changes due to unexpected soil conditions shall be submitted to the Department of Building Inspections for approval.

The designer may use the foundation chapter in the current edition of the IRC or International Building Code to assist in the structural design of the proposed foundation system. The design shall include the general soil condition, a footing and foundation wall design, foundation drainage, and type of material to be used for backfill. All foundations shall be designed in accordance with accepted engineering practices.

The designer’s name (not business name), address and occupation shall be both on the soil test report and the proposed foundation system, to be supplied to this office.

It is the recommendation by the Department of Building Inspections that all sites for new residential construction be tested for shrink/swell soils by Virginia registered soil scientist. If shrink/swell soils are encountered the foundation shall be designed by a Virginia registered design professional.