Your home’s foundation is cracked and damaged, just your luck. You would think that the strong base your home is built on would last forever. Now you’re deep into the “why-s,” as in: Why do things break? Why do things fall apart that seem like they should be indestructible?
At Anchor Foundation Repair, we have been inspecting and repairing home foundations in Bryan, College Station, and other Brazos Valley communities like Navasota and Brenham since 1985. We have seen *more than our fair share* of damaged and cracked foundations and can tell you about how this happens.
You’re right, it seems like concrete should last forever, but alas it does not. It’s pretty strong, but sometimes other things are stronger.
Like anything else in this world, slab-on-grade foundations can move, break, crack, or be damaged over time. Three main conditions lead to foundation settlement and damage to your home: expansive clay soil plus climate inconsistency, under-slab plumbing problems, and poor initial construction.
Let’s check out these 3 most common causes of slab-on-grade foundation cracks and damage in our Central Texas area now.
1. Soil and Climate Extremes Can Cause Foundation Damage
The combination of the properties of our local soils plus a *special* climate with wet and dry extremes creates a special recipe for foundation damage. The two forces of expansive clay soils and inconsistent climate conditions work together and strongly impact your home foundation.
This soil/climate interaction is the top cause of foundation damage and problems in the US, causing more damage and costing more money annually than damage from hurricanes, tornadoes, earthquakes, and other natural disasters combined.
Expansive Clay Soil Properties
Throughout Central Texas where we live, expansive clay soils dominate the landscape east of I-35 (and are also present in many other areas of the US). We have written a whole article just on this topic but in a nutshell, expansive soils expand and contract based on moisture levels.
The molecules in the soil puff up when wet and deflate when dry. The molecules are packed closely together and push out all the way around (like inflating a ball), but because they are tightly packed they can’t push out very well on the sides so they push up instead (where there is less resistance) and with much more power on your home’s foundation during rainy seasons.
Then when it’s dry, they sink down and retract to a smaller molecule size and let your foundation fall back. The forces of expansive clay soils on your home are like daylight savings time on your foundation, springing forward (up) and falling back every year. Repeat this pushing and falling effect over and over again through the years.
Like bending a paperclip back and forth until it breaks, your home’s foundation will begin to weaken and sometimes break due to these strong seasonal forces, and then it moves from its original position. This is what we call “foundation settlement” in the industry, which is also a nice way of just saying that your foundation is sinking.
Inconsistent Climate Conditions
Now combine expansive clay soil with our delightful weather patterns. Sometimes we get a lot of rain for extended periods, and then we will get no rain. Like none . . . for a long time . . .
Our rainy and drought seasons tend to be *kind of intense* (to put it nicely). Sometimes there are heavy rain patterns for extended periods. Then the rain stops and it becomes bone dry for months on end.
If it were dry here all the time, the expansive soils wouldn’t expand. If it were wet here all the time, the expansive soils would stay expanded. If there were consistency in the climate, this wouldn’t be such a problem for your foundation but “inconsistent climate conditions” is kind of a thing around here.
2. Under-Slab Plumbing Problems Can Cause Foundation Issues
Under-slab plumbing leaks are the second most common cause of foundation damage, but it’s a far second compared to the No.1 cause of expansive soils and climate.
Leaks from plumbing lines under your home contribute excess moisture to the expansive clay soil under there too. Remember what moisture does to our soil? If drain lines are leaking under your home over a prolonged period, it causes the soil to heave and pushes your slab up and it can move, crack, or break.
Leaking water under a home can cause poorly packed soil to “wash out” and create erosional voids or empty space under the home. Voids lessen the support under the home and can cause a slab to crack or break as well.
Broken plumbing lines leaking water can also attract tree roots to the water and those roots are powerful damagers of both plumbing lines and foundations over time.
Time is the enemy with under-slab plumbing leaks. You can’t see them and have no idea how long they have been going on until you begin to see damage or problems caused by the leaks. The longer the plumbing lines leak, the more foundation movement or damage can happen.
Under-slab plumbing leaks are also one of those, “Which comes first, the chicken or the egg?” situations where it’s hard to know what caused what first. Did the plumbing leak cause the foundation movement or did foundation movement cause a plumbing leak? Either way, your foundation can be damaged and could need repair.
Plumbing issues are a big reason people have to quickly decide to get their foundation repaired, rather than waiting a bit and monitoring for changes before making the decision to repair a foundation.
3. Poor Initial Construction Can Cause Foundations to Crack
Poor construction can be a cause of foundation problems. We are listing it last here because it is not very common. Poor construction can be rooted in workmanship issues or in building codes.
Issues of Workmanship
There are some cases where poorly prepared grade (aka ground) can cause instability in the foundation. When mixing and pouring concrete, builders also have to watch the ingredient and temperature levels. If the concrete is not mixed properly or the ingredient proportions are off, it can affect the durability of the foundation.
If it’s too cold or rainy when they pour the concrete for the foundation, that can weaken the material.
Instances of poor construction methods causing the foundation issue are rare but we want to acknowledge their existence in the spirit of thoroughness. We tend to have good builders and contractors in the area, but sometimes even when following best practices, individual mistakes can happen.
Building Code Evolution
Building codes help to establish minimum construction standards in most areas and will help ensure that homes are well built. But building codes evolve and are updated as construction methodology improves and/or as insufficiencies are identified.
Codes continue to change over time as more knowledge about *how things are working* develops.
A builder can follow all the codes and essentially “do everything right” at build time and still, issues can come up in the future. Something that was okay 40 years ago might have a stricter code now if problems were identified with the method, material, or technology.
So older homes might be more susceptible to construction method failures or rural homes may not have been subject to any building codes at all depending on how far outside of a municipality they are located. Just something to keep in mind in case your home is *of a certain age* and/or in the country.
What To Do About Damaged and Cracked Foundations
Now that you know the top 3 causes of damage to foundations, you’re probably wondering what to do about them next. People do tend to worry particularly about cracks in their slab foundations.
At Anchor Foundation Repair, we have been assessing damaged and cracked foundations for 35+ years in the Brazos Valley. Homeowners tend to panic every time they see a crack in their foundation, but not all of them are something to worry about.
To see why not all cracks are created equal, check out our article, “Should I Worry (& What to Do) About Cracks in My Foundation? 7 Types,” for some eye-opening information.