What is soil heave and what if it happens around my home? What causes the issue and what signs should I look for to know if heave is affecting my slab foundation? And while we’re at it, how can soil heave be prevented and repaired?
At Anchor Foundation Repair, we’ve been assessing and repairing Brazos Valley foundations for 40+ years. We know the key indicators of foundation settlement as well as soil heave and how to tell the difference. Although soil heave happens far less often in our area, we can explain what soil heave is and how it can affect your home.
In this article, we define soil heave with a focus on how it affects slab-on-grade foundation homes. We explain the typical causes of this issue for Central Texas homes. We discuss signs as well as preventative measures and repairs.
What Is the Definition of Soil Heave?
Think of what the word “heave” means by itself. Similar words like lift, raise, swell, rise, displace, elevate, and push all come to mind. Well, those things are what happens when soil heaves.
Soil heave is the opposite of soil settlement. With settlement, the soils in our area contract, shrink, and sink due to dry conditions. With heave, the soil expands in prolonged wet conditions. Soil heave will lift, push, and raise the soil and anything on top of it, like your slab foundation. In a nutshell, it’s the upward movement of soil.
Soil heave is a mighty powerful force. It’s concerning to us humans when heave affects the structural stability of homes and other buildings, causing both unsightly damage and unsettling symptoms. Besides homes and structures, heave can also easily affect smaller concrete flatwork, like sidewalks and driveways, or other items like retaining walls and even brick mailboxes.
What Causes Soil Heave to Happen Around a Home?
Expansive clay soil is prevalent throughout the United States, and even more so here in Central Texas. This type of soil is particularly reactive to moisture (as well as dryness), and it swells or expands when wet – hence the name *expansive* soil. The longer an expansive clay soil remains soggy, the more it swells.
So it doesn’t take a genius at this point to realize that what causes soil heave is excess moisture, usually in liquid form, also known as. . . water! Common causes of extra water hanging out around a house are:
- Poor drainage,
- Compromised plumbing lines,
- Leaky pools, or
- Heavy rains.
You can certainly blame the dirt and water for soil heave when it happens. However, you also play a part in the process if you allow water to remain around your home and don’t do anything about it.
Water should not just sit and pool around your house or underground near your home. This is why people invented things like gutters and French drains. It’s important to monitor your drainage situation and rectify water-related issues right away if they occur.
A less obvious cause of heave can come from intrusive tree roots pushing up on the foundation. Though the heave is not coming from the soil itself, it’s coming from root pressure. Sometimes construction of houses, streets, or curbs close to your home create new drainage issues for you due to a change in landscape. The change can inadvertently direct water towards your home and possibly cause soil heave on your property.
What Are the Signs That Soil Heave Is Affecting a Foundation?
Soil heave creates conflicting signs, presents inconsistently, and is difficult to diagnose. One area of your home will be affected and an adjacent area will seem perfectly fine.
Common signs of soil heave include:
- Cracks in walls,
- Floor cracks,
- Sticking doors and windows,
- Or a noticeable hump in the floor.
In homes with basements, soil heave can even cause the basement walls to push inward or cave in. Luckily, we don’t typically have basements around here!
Signs of soil heave affecting your foundation are difficult to differentiate from settlement signs. Settlement also causes wall cracks and sticking doors and windows so it’s easy to get confused.
Soil heave is best discerned by looking closer at the directions of cracks and understanding the relationship between the specific signs that appear in your home. It’s best to ask a foundation inspector to assess your home if you think soil heave is occurring. A foundation professional can confirm if it’s truly soil heave messing up your foundation or the more likely cause of foundation settlement.
How Can I Prevent Soil Heave From Damaging My Home?
Preventing soil heave is all about keeping the water away from your home. Assess the drainage situation around your foundation. If you have a recurring drainage issue, it may take several layers of *effort* to work through and get the drainage situation under control. This might mean:
- Adding, repairing, or improving gutters,
- Adding downspout extensions or underground downspouts that go to the street,
- Working on soil grading, ensuring it slopes away from the home,
- Adding surface drainage facilitators like swales or berms,
- Adding underground drainage like catch basins or French drains, or
- Improving moisture management if you happen to live in a crawl space home.
Excess water is the enemy when it comes to both soil heave and even contributes to soil settlement. Plan to slowly work on drainage issues until water can quickly move away from your foundation.
Non-drainage-related management and maintenance includes:
- Fixing plumbing leaks right away,
- Avoid purposefully planting large trees near the home,
- Removing *surprise sprout up* trees near your foundation,
- Maintaining a leak-free pool, and
- Making sure your irrigation system is leak-free too.
These non-drainage preventions are things to handle right away. Don’t let these issues linger because that’s how heave can happen (P.S. They can cause settlement too).
Can Soil Heave Issues Be Repaired?
Repairing heave damage can be tough. Honestly, there’s no great way to “fix” foundation issues caused by heave. Once heave occurs, you can address the water source feeding the problem by improving drainage and repairing leaks. You can repair drywall after the heave has settled down and get doors working better with a few makeshift solutions.
At this moment, there is no prescribed repair available that we know of to push a heaved slab foundation down to its original position. The best you can do is hope that it moves back down on its own once you’ve rectified the water problem causing the soil to expand.
Foundations do move up and down every year with seasonal settlement and rebounding cycles. So as long as the source of the heave is gone, your foundation could settle back down into an improved and unheaved position. But it also might not fully return to normal . . . sorry, that’s probably not what you want to hear . . .
How Often Does Soil Heave Happen?
The good news is that heave is much less common in our Central Texas area so we don’t even see good examples of it very much. We have way more problems with prolonged dryness aka drought than we do with prolonged rainfall for the most part.
Even when we do have what seems like excess rain, it doesn’t last for months. It’s more like, we get a hurricane or strong storm and it’s really bad for a short time but then it’s gone and everything dries out fairly quickly.
For heave to happen around here, it’s more likely to come from a prolonged and excessive underground leak that you don’t even know is happening. A long-term pool leak could be a likely culprit, or heavily leaking drain lines from a building that uses a ton of water for some reason – maybe a laundromat??? I’m just guessing here!
What Should I Do Now To Care For My Foundation?
Now that you know all about soil heave, you need to know about settlement signs too because that is a more likely culprit around here. Check out this picture guide for a complete look at both true and confusing signs of foundation problems.
At Anchor Foundation Repair, we understand the stress and anxiety that come from concerning signs and symptoms you see around your home. After 40+ years in business, we want you to know as much about foundation issues as we do and we’ve got no secrets to hide from the Brazos Valley community.
Prevention and maintenance are the best ways to keep troublesome issues from developing around your foundation. Try The Best Maintenance Checklist to Care for Your Foundation.
