Denver Soil Composition: How To Protect Your Home

Remember when you first became a homeowner? Wide-eyed and with little knowledge of the journey ahead. Now, here you are… reading blogs about soil composition and foundations. 

In all seriousness, understanding the soil surrounding your home is a wise move, and you deserve a round of applause for it. This knowledge is crucial for knowing what’s happening beneath your home, how you can provide support, and ways to address current issues. 

Here in Denver, the unique characteristics of our soil can have a significant impact on the stability and health of your home. And that’s why, in this blog, we’re sharing everything you need to know about Denver soil and how it affects your foundation. Let’s dive in. 

Soil 101

Before we talk about the soil in Denver, it's important to know a bit about soil itself. It's much more than dirt under our feet – it's a complex mixture that supports life on Earth and supports your home. 

What is soil?

Soil is the top layer covering the Earth's surface. There are five soil horizons: the organic layer (called humus), topsoil, subsoil, weathered rock, and bedrock.

Components of soil

1. Minerals: These come from weathered rocks and provide structure to the soil. 
2. Organic matter: This includes decomposed plant and animal material, which enriches the soil with nutrients and helps retain moisture.
3. Water: Water fills the spaces between soil particles and dissolves nutrients.
4. Air: Soil needs to be porous for air to circulate. 

Types of Soil

Soils are categorized into several types, primarily based on the size of their particles. The three main types are sand, silt, and clay.

Soil primarily consists of three main types: sand, silt, and clay. However, the composition of soil can often be a combination, such as silt loam, or sandy clay. This chart shows a lot of the various mixtures.

Denver’s soil composition

Denver soil, and actually, most of Colorado, is mainly made up of three types: sandy, clay, and bentonite. Let's break down each of these soils for those not well-versed in geology (and for those who are, hi there!).

Sandy Soil

Sandy soil is mainly made up of big particles from rocks like granite. It feels gritty and doesn't hold water well, so it dries out fast and doesn't have a lot of nutrients. 

You guessed it—sandy soil looks just like, well, sand.

Sandy soil has its ups and downs when supporting a foundation. The good part is it drains water really well, so you don't get water hanging around your foundation, causing damage. It's also pretty stable and doesn't change shape much, which means your foundation is less likely to move or crack. 

However, there are a couple of downsides. Since sandy soil can wash away easily in rain or wind, it might not always support your foundation as strongly as you'd like. And because it doesn't hold water and nutrients well, growing plants around your foundation can be a bit tricky. So, while sandy soil can be a good base for your house, you might need to take extra steps to protect against erosion and make sure it's strong enough to hold up your home.

Clay Soil

This picture shows clay soil that has dried out, causing it to crack. When it's moist, clay soil turns into a thick, sticky mud.

Clay soil is just like the stuff from art class – heavy, sticky, and moldable. It's made of really tiny particles that stick together tightly. When wet, it gets pretty squishy and can be molded easily, but when it dries out, it becomes hard and can even crack.

When it comes to your house's foundation, clay soil can be a bit of a headache. Because it expands when it gets wet and shrinks when it dries, this soil can move a lot. Imagine the ground beneath your house swelling up like a sponge and then shrinking back down. This movement can cause your foundation to shift, crack, or even break. 

Bentonite Soil

Fun fact: Bentonite is super absorbent and clumps together really well, which is why it's a popular choice for kitty litter.

Bentonite soil is a really unique type of clay that behaves kind of like those super-absorbent materials you find in diapers. 

It's made up of tiny particles that can swell up a lot when wet. In fact, bentonite can absorb so much water that it can increase its size several times, turning into a really gooey, sticky mess. When it's dry, however, it becomes super hard and can crack. 

Like clay soil, bentonite soil can be a real challenge for your foundation. Its ability to swell massively when wet and then shrink when dry can put a lot of stress on your foundation. This constant change can make the ground unstable, causing your foundation to move, crack, or even heave. 

How the Soil Affects Your Foundation

Unlike the more stable soils in the Midwest, Denver's soil composition tends to have more movement and expansion, resulting in more heave conditions. This creates unique challenges for home foundations, as the soil is more prone to shifting and settling.

What is heave?

Heave is when the ground under your house moves upwards. It happens when the soil swells up and pushes the foundation of your house from below. 

When certain types of soil, like clay or bentonite, get wet, they can soak up water like a sponge and expand. This expansion causes the ground to push upwards, which can move your house's foundation. Imagine placing a sponge under a heavy book and then getting the sponge wet. As the sponge swells up with water, it lifts the book. That's similar to what happens to your house during heave. This upward movement can cause cracks in your walls, uneven floors, and other structural problems in your home.

This image depicts soil pressure from beneath the home moving upward.

Identifying Soil Types Around Your Home

If you’re curious about the soil surrounding your home, there are a few ways to discover what kind you have. 

You can contact your local planning department of your municipality, check with your county clerk’s office, ask your homebuilder, or check with your HOA. Our favorite way is to go to the USDA’s Web Soil Survey – a website that holds a lot of data on soil around the United States. Here’s how to find your soil info: 

1. Go to this website: USDA’s Web Soil Survey
2. In the lefthand column, insert your location – either your address or state and county. Hit View.
3. Next, select the AOI icon above the map. This is your “Area of Interest”, AKA the spot where you want to learn about the soil.
4. Outline the area where your home is.
5. After, head over to Soil Map. 
6. In the lefthand column, you can find the soil details in your AOI.

Outline your AOI using the icon highlighted and then select the Soil Map tab to view your soil details.

Knowing your soil type helps protect your home

Now that you know about Denver soil composition, here’s how you can use this info to your advantage.

Better water management

A proper drainage system has fully functional gutters that effectively divert water away from your home. Plus, if you need assistance setting this up, we can help.

Different soils deal with water in their own ways. Clay soil, which you find a lot around here, swells up when it gets wet and shrinks when it dries out. This can make your house’s foundation move. Sandy soil, though, lets water drain through it easily, which means less trouble for your foundation. By understanding what kind of soil you have, you can make sure water drains well around your home. This might mean fixing your gutters, putting in pumps, and choosing the right plants for your garden.

Better landscaping decisions

The type of plants and trees you have can change the moisture level in the soil and affect your foundation. If you know your soil type, you can choose the right greenery. For example, big trees planted too close to a house with clay soil can make moisture levels go up and down, which might cause problems for your foundation.

Better drainage

Our team installing an interior floor drain to help a homeowner better manage their clay soil and improve their home's drainage system.

Good drainage stops foundation problems before they start, and knowing your soil type helps a lot with this. With this knowledge, you can add things like French drains (If you want to know more about French Drains, this blog explains the entire system) or make small changes to the grading to help water move away from your home.

Knowing the signs

Understanding how your soil and foundation interact helps you catch issues early. This means you can fix small problems before they turn into big, expensive ones.

By using what you know about your soil, you can make smart choices to keep your Denver home safe and sound. Whether your yard is full of clay, sand, bentonite, or something in between, a little bit of knowledge goes a long way in looking after your place.

Foundation Repair Methods for Denver Homes

Helical piers work to counteract the issues caused by expansive clay and foundation settlement. They do this by drilling down to bedrock, a much more stable layer, which then supports the weight of your home.

Because we’re foundation repair contractors, we’ve been in a lot of Denver homes and see a lot of the same thing. Most homes in this area have crawl spaces and caissons to mitigate heave issues, but sometimes there are still issues. 

The most common are cracks in brick, drywall cracks, doors and windows malfunctioning, and visible cracks in the foundation. If you're questioning whether that odd crack in your wall is a concern, we've got a useful guide to help you determine if it's a structural problem.

When our home specialists inspect these areas, we find that piers, power braces, and wall anchors are the best foundation methods for Denver soil. 

Soil is the problem and the solution

Knowing about the special soil and weather in Denver is really important for homeowners to keep their house foundations in good shape. If you understand the kind of soil, possible foundation problems, and the right ways to build and fix things, you can take better care of your home. This way, you can make sure your home lasts a long time in this lovely but tough area.

And hey, nice to meet you! We didn't introduce ourselves earlier, but we're Thrasher Foundation Repair, a foundation and basement contractor with almost 50 years of experience. When it comes to foundations, we've got the know-how.

If you happen to be in Colorado or in our service area, we’re here to help with any soil questions, cracks you're seeing in your home, or even just chatting about life – we’re up for that, too. You can reach out to us by calling us at 1-800-827-0702, filling out this form, or starting a chat in the bottom right-hand corner.