Does your building site have high clay content? In this video, Matt Risinger, master builder shows us how clay soil can wreak havoc with your concrete foundation. Being able to tell how much clay you might have is key. Clay has an expansive property which can cause slabs to crack because that clay was exerting pressure. It expands when wet and contracts when dry and when it exists, the engineer should specifically design your foundation to resist those forces. Estimating is no replacement for a geoengineer's report which can tell us how much that soil is going to move and whether or not there is rock. Risinger shows us an excavation. Looking at the top 1-2 feet, the soil is very black, which is good soil. However, if things go rapidly from back to tan, the color change is the first indicator of a soil switch. If you take a handful of clay and add water to it and compress it and see if it acts like PlayDough. If it does, there's a lot of clay. Knowing is the first step, what to do with it will be another video.