How Soil Affects Your Foundation

Ever heard the tale of two builders? One chose sandy soil for their foundation, the other solid rock. When a storm rolled in, rain and wind tested both homes. The sandy house quickly washed, but the rock-based home stood strong, unphased!

Just as this story illustrates, soil matters. We can focus on how homes are built and look, but the soil they sit on is crucial! Changes in soil composition can seriously affect your home's long-term stability. Let's explore how soil erosion impacts your foundation. Ready to dig in?

Wall cracks, both inside and outside the home can be a sign of larger foundation problems.

Signs of foundation problems

Soil shifts and changes over time, but how can this be shown in your home?

• Cracks in walls and floors

• Sagging and unlevel floors

• Bowing walls

• Sticking windows and doors

• Tilting chimney

All these warning signs are your home trying to tell you about the shifting soil underneath. These issues won’t fix themselves, and if ignored, small cracks will only become more dangerous and expensive to repair.

What is foundation soil?

So, what exactly is foundation soil? Soil has different compositions, but for the most part, it's a mix of clay, sand, minerals, organic matter, water, air, and rock. Each layer of soil tells its own story of how rain, wind, and erosion have shaped it over time. Some soil layers are more dramatic than others when it comes to these weather changes. Lean in, here's the dirt on soil types.

Sandy: Water doesn't have a huge effect on sandy soil; rain easily filters through it. Sandy soil maintains its volume and density whether wet or dry. It rarely causes foundation problems because it remains stable without shifting or settling much.

Clay: Clay is the most problematic for foundations. It absorbs water easily and swells like a sponge when wet. This expansion can heave, shift, and crack foundations. When clay dries, it shrinks and forms gaps, worsening foundational stability. This cycle intensifies as the soil saturates and dries out, causing more serious issues.

Sandy Loam: This soil type is usually stable and shows little change with varying moisture levels. Sandy loam soil is a mixture of sand, silt, and clay. This soil easily erodes, making it unable to hold the weight of your home over time.

Bedrock: The deepest soil layer is made of solid, unbroken rock that provides an extremely stable foundation for your home to rest on. When looking to stabilize your home permanently, reaching bedrock is the best option. Bedrock ensures minimal impact from changes in layers above, offering a reliable and permanent solution.

Sandy

Clay

Sandy loam

Bedrock

How does soil cause foundation problems?

Foundation problems arise when the soil can no longer support the weight of your home. Here are the most common reasons for this:

Water can pool due to poor drainage systems, impacting the foundation soil below.

1. Dry Soil: Often caused by drought or mature trees absorbing excess moisture from the soil. Dry soil shrinks, creating gaps between foundation walls and the surrounding soil.
2. Wet Soil: Typically, due to heavy rain, flooding, or inadequate drainage. Wet soil causes soil to expand and put pressure on surrounding foundation walls, leading to heaving and bowing walls.
3. Frost Heaving: When water turns to ice, it expands by about 9%. This creates an excessive amount of pressure on foundation walls, pushing them inwards. As ice melts, voids are left behind.
4. Poorly Compacted Fill Soil: During construction, the original virgin soil is excavated and replaced with backfill soil. However, because of excavation the backfill soil is broken up and loosened. Foundation soil compaction is crucial, otherwise, it will easily fill with water and fail to support your home.

The Active Zone is the layer of soil directly below the home.

Understanding the "Active Zone"

We’ve covered how different types of soil under your home can lead to foundation problems. Now, let’s take a closer look at where these changes are taking place. The soil directly underneath your home is what we call the active zone. This zone is super sensitive to changes in moisture and climate. It often includes layers of clay or poorly compacted backfill soil and can range from just a few feet deep to over 30 feet.

If your home sits in an active zone, the soil may struggle to hold up your house over time, which can lead to foundation problems like sinking or excessive pressure. Knowing where the active zone is can help you catch and fix foundation problems before they become serious.

Solutions to soil problems

Now that you know more about the soil around your home, here's how you can use that info to your advantage:

Soil Improvement: Adding materials like sand, gravel, and organic matter can improve the drainage and stability of soil. Changing the plants and trees planted around your home can help control moisture levels.

Proper Drainage: Good drainage stops foundation problems before they start. Redirect water away from your home through gutters and French drains.

Seamless gutters don't just drain water, they also keep out leaves and other gunk that can clog gutters!

Unfortunately, if signs of foundation issues are already visible, it is best to consult a foundation expert to understand permanent solutions to relevel and stabilize your home.

Foundation Repair: Repairs like wall anchors, beams, and piers are permanent solutions that connect your home to solid soil or bedrock. This ensures your home’s weight will be properly supported regardless of weather conditions.

Contact a foundation expert

If you have a foundation problem, we recommend calling a trusted foundation repair contractor. If you're in our service area, we're here to lend a hand!

Our team of experts offers free at-home estimates. We’ll inspect your foundation, explain the issues, and recommend solutions. You’ll receive a detailed solution plan and a no-obligation quote during our visit. Contact us today to start tackling the soil shifts affecting your home!