Soil testing for building a custom home is a crucial step in the process for many locations. In this blog post, we will address several questions regarding soil testing:

What Is Soil Testing
Residential soil testing for building, also known as geotechnical soil testing, is the process of analyzing soil samples from a construction site to determine their composition, strength, and other engineering properties. This testing provides valuable insights into the soil’s suitability for supporting various structures, including new custom homes. Soil engineers and geotechnical experts conduct these tests using specialized equipment and techniques.
Why Is Soil Testing Important?
It’s important to understand what is the purpose of soil testing for construction of a new home. Lets review the key benefits.
Foundation Design and Stability: Soil testing helps engineers assess the load bearing capacity of the soil. Different types of soil have varying capacities to support weight. For instance, clay soil has different properties compared to sandy soil. Understanding this allows engineers to design your custom home’s foundation so that it can withstand the specific soil conditions ensuring a stable new home.
Preventing Foundation Settlement: One of the most common issues faced by homeowners is foundation settlement, which occurs when the soil beneath the foundation compresses unevenly. This can lead to both structural and cosmetic damage, such as damage and cracks to walls and other issues. Soil testing helps in identifying these problems beforehand, allowing engineers to design foundations that mitigate these risks.
Optimizing Foundation Type: Depending on the soil test results, engineers can recommend the most suitable type of foundation for the custom home. Common foundation types include slab-on-grade, crawl space, basement foundations and pile foundations. Soil testing helps in determining which foundation type will best suit the soil conditions of your site to ensure long-term stability of the home.
Water Drainage and Soil Expansion: Soil testing also assesses the soil’s drainage properties and potential for expansion and contraction due to moisture changes. Expansive soils can exert significant pressure on foundations, leading to structural damage. Proper drainage solutions can be implemented based on soil test results, preventing issues related to water accumulation and soil movement.
Ensuring Compliance with Building Codes: Many local building codes and regulations require soil testing before and during construction. Compliance with these codes is essential to ensure the safety and integrity of the new home. By conducting tests, builders and homeowners can avoid legal complications and delays in the construction process.
How Is Soil Testing Done?
So, we now understand why soil testing is important, but how do they do it? Soil engineers take soil samples by boring holes in the ground and examine the soil itself. Samples can be taken from shallow bore holes that are dug 3-5 feet by hand or they can take deep boring holes that can go quite deep that require drilling equipment. Depending on the location, engineers can take from 2 to 10 samples, to test the soil, water table and for bedrock and harder soils. How many samples are taken will depend on the size of the project, the location, and the soil engineer. Once the soil borings are collected, some examination will be done at the site while other examinations are done by laboratories with expertise in soil composition.

Where Can You Find Soil Testers?
Soil testers and geotechnical engineers can be found through various sources, both online and offline. Most builders and engineers that are involved in your local residential market will know the geotechnical firms that do this work in your area. Additionally, you can locate them through a simple online search.
When Should You Do a Soil Test?
Soil testing for constructing a new custom home is typically performed before construction begins and depending on other factors there may be additional testing during the construction of the foundation. Some homeowners request a soil test before land is purchased and put that their offer is contingent on an acceptable soil test result.
How Much Do They Cost?
The cost of a residential soil test can vary based on the method you choose and the number of borings and depth that are required. Our experience is that a soil test with 1-2 deep borings and 3-4 shallow borings is typically in the range of $1500 to 2500, but getting a quote and finding out what is necessary for your lot is an easy, quick process.
Conclusion
As you can see, soil testing is a critical step in the construction of a new home, offering invaluable insights into the soil’s properties. By paying for soil testing upfront, you can ensure that your design and construction uses a strong foundation that is stable and safe. From preventing foundation settlement to optimizing drainage solutions, soil testing provides a wealth of benefits that far outweigh the initial cost. As a homeowner, it is important to work closely with experienced engineers and geotechnical experts to conduct thorough soil testing and site evaluation before embarking on the exciting journey of building your dream home. By doing so, you are not only securing the future of your investment but also ensuring a safe and stable haven for you and your family for years to come.
Additional Resources
DIY - Article discussing whether you can DIY soil testing
Mistakes - Some errors to avoid when doing soil testing
Types of Tests - Here is an article on the different types of tests
Legal - An article on soil testing from a legal standpoint
Video - A link to a video of a builder working with a geotech to do a field test