You’re buying your first home, planning on making an addition. Life is good.
Or is it? You closed on the house without noticing cracks in the exterior walls from the foundation settling over the years of the house sitting on it. Soil testing for construction or for buying purposes might seem like an extra hassle until your foundation is twisting and cracking.
Foundation repair can be costly and may have been unnecessary if you did your homework before buying or before putting shovel to clay.
Let’s dig into the tests you shouldn’t ignore.
What Are the Different Soil Tests?
There are dozens of specific tests on soil to find out its various qualities such as water content and compression characteristics. These tests help to find out the problems you might encounter during the essential foundation-laying steps of your construction project.
Soil testing is just a small part of environmental testing and surveying.
We’ll go over 6 tests that you never knew you needed.
1. Specific Gravity
Specific gravity is a test against the density of water. That is, whether your soil will sink or swim. It’s very important to know if the soil under your house will turn to mud and float away during a flood or other major weather system.
2. Dry Density
Equally important, a test of density while dry will determine the density of your soil when dry. While sand seems to be quite dense, this dry density test is about voids or open spaces between soil particles.
Clay, for example, has very few voids when compared to sand which is generally quite porous.
3. Atterberg Limits
There are two major limits tested in this series, which determine fine-grained soils’ plastic limits, and a liquid limit test or the liquid required to fill a void. The liquid limit test uses a testing tool called the Casagrande apparatus.
The liquid limit test determines the water content required to close a gap within a specified number of blows within the Casagrande apparatus. The plasticity test involves making some clay-like strips 3mm wide until they do not break.
Then moisture content is determined.
4. Proctor’s Compaction
Proctor’s compaction is a long process of getting a specific water content in the soil, compacting it to a specific volume, and testing a plug of the soil. Density will be a function of the water content once it’s plotted on a graph.
5. Moisture Content
Moisture content is a test that is performed multiple times as part of multiple tests. Though there is one that must be taken standalone without any alterations or mechanical changes to your soil, to find out the native water content.
this will determine how your soil will perform in the wild, so to speak.
6. Foundation Testing
Ultimately, before you put in your footers and start pouring your concrete, you’re going to want to do last-minute foundation testing. If you don’t think it is important, wait 6-10 months until your windows and doors don’t open and close. Then the cracks form (ouch).
Make sure to have a geotechnical engineer come by and probe the footers before that first pour!
Soil Testing for Construction: Forming Up
In summary, soil testing for construction is an essential practice. Even many states, including New York, now make it a mandatory practice. If it isn’t mandatory in your area, it doesn’t mean that testing isn’t important.
Before you put shovel to dirt, make sure to contact us and read on for more environmental and land surveying tips!