Looking at fixing concrete floor cracks? Don’t freak out — But don’t Ignore them either. If you’ve got concrete floor cracks, you’re not alone. Floor cracks are one of the biggest concerns homeowners have, especially in North Texas where the soils are shifting and the weather is extreme. Some cracks are just cosmetic, but others are warning signs your foundation is failing. The key is knowing the difference — and why the crack happened in the first place.
Guide to Fixing Concrete Floor Cracks Includes:
- Why do concrete slab floors crack
- The different types of cracks and what they mean
- DIY tips for filling and sealing minor cracks
- Why you should never fill heaving cracks caused by plumbing leaks until you fix the leak itself
- How drainage plays a critical role in crack prevention
- When it’s time to call Arch Foundation Repair
Why Do Concrete Slab Floors Crack?
Concrete is tough, but it’s not bulletproof. Here are the most common reasons cracks form:
Soil Movement: Texas clay soils expand when wet and shrink when dry — putting constant stress on your foundation.
Moisture Issues: You may notice plumbing leaks, poor drainage, and pooling around the foundations. It all makes soil less stable. Eventually it leads to foundation cracks.
Settlement: Over time, soil under the foundation can shift unevenly. It leaves the slab unsupported in spots.
Temperature Swings: Concrete expands in the heat. When it is cold, it contracts. This leads to surface cracks.
Types of Concrete Floor Cracks (and What They Mean)
| Type of Crack | What It Looks Like | What Caused It | Should You Worry? |
| Hairline Cracks | Thin, surface-only | Natural curing | Cosmetic |
| Settlement Cracks | Wider, uneven edges | Soil settling | Moderate to serious |
| Heaving Cracks | Raised, jagged edges | Soil swelling or plumbing leak | Serious |
| Moisture Cracks | May look discolored | Water under slab | Needs investigation |
| Structural Cracks | Deep, zigzagging across the floor | Foundation movement | Serious |
How to for Fixing Concrete Floor Cracks in Your Slab
Filling and Sealing Cracks You Can Handle Yourself
If your cracks are small (under 1/8 inch wide) and not caused by foundation movement, you can fill and seal them yourself to protect against moisture and dirt.
What You’ll Need:
- Crack filler/sealer (see options below)
- Wire brush
- Vacuum or blower
- Caulking gun (if using a tube product)
- Trowel or putty knife
- Painter’s tape (optional for neat edges)
Best Products for Filling and Sealing Cracks
| Product | Type | Pros | Cons |
| Sikaflex Concrete Fix | Polyurethane Sealant | Flexible, waterproof | Long cure time |
| Quikrete Crack Seal | Acrylic Latex | Easy to apply | Less durable in high traffic |
| Dap Concrete Crack Filler | Latex | Paintable, easy cleanup | Can shrink slightly |
| PC Concrete Epoxy | 2-part Epoxy | Extremely strong | Requires mixing |
| Rust-Oleum Patch & Repair | Epoxy Patch | Sandable, very durable | Short working time |
Step-by-Step DIY Crack Repair
- Clean the crack.
Use a wire brush to loosen debris, then vacuum it out. - Apply filler.
Cut the tube tip to fit the crack width and apply evenly. For epoxy products, mix before applying. - Tool & smooth.
Use a trowel to feather edges into the floor for a seamless look. - Let it cure.
Most products need 24 hours to fully dry.
💡 Pro Tip: Use a concrete bonding agent inside the crack for better adhesion.
Heaving Cracks from Plumbing Leaks — Fix the Leak First!
What Are Heaving Cracks?
Heaving cracks happen when something pushes your slab UP from below. One of the biggest culprits? A plumbing leak under your foundation.
Water leaking from broken pipes (like sewer lines or water supply lines) soaks into the soil beneath your home. In Texas’ clay soil, this causes dramatic swelling — which lifts sections of your slab and creates jagged cracks.
Signs You May Have a Slab Leak:
- Cracks appear suddenly and are raised on one side.
- You notice damp spots on the floor.
- Your water bill spikes for no reason.
- You hear water running when no taps are on.
- Cracks are near kitchens, bathrooms, or laundry rooms.
Why Filling & Sealing Won’t Work (Yet)
If you seal the crack before fixing the plumbing leak, the soil will keep swelling — and the crack will reopen almost immediately. That’s why leak detection and repair is step one.
Plumbing-Related Heaving Crack Repair Process
- Find the leak.
A specialized plumber uses acoustic or pressure tests to locate the leak. - Fix the pipe.
This could mean tunneling under the house, cutting through the slab, or rerouting the line. - Let soil stabilize.
It can take weeks for waterlogged soil to dry and shrink back down. - Assess the slab.
If the floor shifts a lot, you may also need foundation leveling before filling the crack.
Foundation Drainage — Another Key to Crack Prevention
Even if your plumbing is fine, poor drainage around your home can cause serious problems. Water pooling near the foundation softens and erodes the soil, causing uneven settling and (you guessed it) more cracks.
Signs You Have a Drainage Problem
- Puddles form along the house after rain.
- Soil erodes away from the slab.
- Gutters dump water too close to the foundation.
- Mildew or algae grow near the foundation.
Who Can Fix Drainage?
- Plumbers for outdoor leaks
- Landscapers for grading, French drains, and swales
- DIYers can extend downspouts and regrade soil (check out our DIY Drainage Tips)
💡Important: Drainage Comes First: Fix the drainage before filling cracks — otherwise, you’re patching a symptom, not the cause.
Foundation Cracks – When to Call Arch Foundation Repair
If your cracks are caused by foundation settlement, soil shifting, or movement, no amount of sealing will hold up. Foundation repair may involve:
- Underpinning (piers installed to stabilize the slab)
- Slab lifting (foam injection or mudjacking to relevel floors)
- Drainage correction to stop future damage
The Right Order of Repairs (Save This!)
- Fix leaks and drainage.
- Let soil stabilize.
- Check for foundation movement.
- THEN fill and seal.
Contact Arch Foundation Repair for a Full Evaluation
Some cracks are cosmetic — others are warnings. Don’t guess. Let Arch Foundation Repair inspect your foundation and uncover the real story behind your floor cracks. Expect honest advice (no pressure sales). We offer proven solutions tailored to Texas soils. Get trusted referrals to plumbers & landscapers if needed. Enjoy friendly service from experts who care about your home.
Contact Arch Foundation Repair Today or give us a call.
Let’s fix the cause — not just the cracks.
Foundation Crack Series
- How to Repair Cracks Around Window Frames – Quick Guide
- How to Fix Concrete Floor Cracks in Slab? Ways to Great Results!
- How to: Filling Cracks Around Door Frames: Expert Ways to Make it Better
- How to Repair Wall Cracks, When to Worry, & When to Get Help
- How to Fix Ceiling Cracks DIY Tips – Are Cracks in Ceilings Normal?
- Signs of Foundation Problems: Why Does Grout Crack / Why Do Tiles Crack?
- Helpful Ways on How To Seal, Fill & Fix Cracks in Garage Floor
- Why Brick Walls Crack – When to Worry, Get General or Foundation Repairs
- How to Amend Clay Soil: Fill the Gap Between Soil and Foundations
- How to Fill a Gap Between Driveway and Garage & Foundation – Make Helpful Repairs
