Challenge of Blue Clay: Here’s Why You See Cracks in Your Southern Utah Home

A family who recently bought a new home in Washington were surprised to find a crack developing in one of the outside walls. They can't understand why the crack seems to be expanding and wondered if the house is settling.

Problems with Blue Clay in Southern Utah

If you live in Southern Utah, there is a good chance you have heard of Blue Clay. It gets its name from its purple color. You may have heard the nightmares that have happened to people’s foundations and yards from this destructive soil.

It is something to be aware of if you are building or buying an established home. It can cause problems if it gets saturated with moisture.

I talked with Spence Richins with Grass Creek Construction. “Blue Clay is called an expansive soil. Which means when moisture is added to it, it swells,” said Richins. “It causes what is called a heave, meaning it lifts.” This can cause damage to a home. 

A Soil Test is Required Before Building

A builder will call a Geotechnical engineer who takes a sample of the soil to find what is on the property. They give a recommendation for what they find there. Blue Clay swells but there are also collapsible soils that can be a problem.

The report they provide gives advice on what you need to do to keep your foundation stable. The report may recommend zero-scape landscaping to keep from getting too much water in the soil and creating problems.

You can build on Blue Clay, but you have make room in the foundation for it to expand. One way is a micro pile that leaves room or a void for the clay. There are other ways as well. 

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Even an Established Home Can Begin to Slip

You may not be aware of the soil test when you are buying an existing home. This is where the problems can come if you aren’t aware of the initial report from the Geotechnical engineer.

If you buy a home and put in grass or a pool where there was only drip recommended, it can cause problems when the soil gets saturated. You can see damage from Blue Clay just off Bluff St. in St. George.

“It’s a factor that is always there,” said Richins. “So, it doesn’t matter how much you do to mitigate it, the soil could activate.” 

Read More: 5 Great Smaller Communities in Utah to Buy a Home in 2025

This isn’t just a Southern Utah problem, there are different layers of clay and soil that expands or contracts when saturated. You need to be aware what is under your home before you make any big changes that may activate these layers.