• Blake DeMarr, PE

Do I need a Soils Report in Fairfax County, VA?


When preparing a new site plan in Fairfax County for a new home build or pool project, there are certain factors that will require a soils report as part of the site plan submission. When you hire us as your Civil Engineering consultant to prepare Site Plans for your project, we will check the County Soils Maps to determine the level of Geotechnical Investigation required. You will then need to talk to a Geotechnical Engineer such as TERRA Engineering to prepare the Soils Report.


Here are a few helpful links to give a little more information on the requirements of Soils Reports in Fairfax County:

https://www.fairfaxcounty.gov/landdevelopment/soils

Fairfax County Geotechnical Report Requirements Summary


We (and Fairfax County Plan Reviewers) use this Fairfax County GIS Map Soils Viewer to determine generally what soil category your site falls in. This by no means is an accurate representation of the soils on your site, but it provides enough information to raise red flags on if your site falls in a "problem soil" area. We use the County Maps to determine if your site is in a "Class III or Class IV" soils area, which are considered "problem soils." Straight from the Fairfax County Manual: "A geotechnical report, prepared according to the geotechnical guidelines in this chapter and the Virginia Uniform Statewide Building Code (USBC) is mandatory for all construction and grading within these problem soil areas." There is no way around this. If your site is in a problem soils area, you will need to hire a Geotechnical Engineer to prepare a Soils Report before we can submit our Site Plan for county review and approval.


The next step will be for the Geotechnical Engineer to visit your site to take hand-auger borings and/or machine test-pit samples of the soil of where you plan to build your new home or pool. They will then prepare a report to profile and categorize the type of soil on-site along with recommendations on the foundation for proper soil bearing strength.


IMPORTANT: Even if we determine that a Soils Report is not required for County Approval, we still recommend a Limited Soils Investigation & Report by a Geotechnical Engineer regardless. Having a Licensed Geotechnical Engineer prepare a soils report for your new home foundation is added insurance that you are building on solid ground.

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