Serving Greater Waterloo

Concrete Floor Repair

Crack, spall, joint and scaling repairs for garage, basement and commercial slabs, with an honest call on when a slab needs replacing instead.

Waterloo Epoxy Flooring handles concrete floor repair in Waterloo, IA, serving surrounding cities including Evansdale, Cedar Falls, Waverly, Independence, Oelwein. After more than 20 years preparing slabs for coatings, we know that most floors need some repair first, and that the repairs decide how long the finished floor will look good.

Cracks, spalls, scaled patches and broken joints are mapped on the first visit, before we write a price. Each one is noted with the repair method, so the proposal shows exactly what will be fixed and how.

We are also honest about the floors that should not simply be patched. A slab that has heaved, sunk or broken apart needs replacing, and covering it with a coating only hides the problem until it returns.

Cracks in Concrete Floors

A chased-out crack and a spalled corner filled flush with repair mortar in a Waterloo shop slab, ready to grind before coating.

Shrinkage and Hairline Cracks

Almost every concrete floor cracks as it cures and shrinks. Fine shrinkage cracks are usually stable, and we repair them by routing them open slightly, cleaning them out and filling them with a rigid repair material. Once ground flush, they typically disappear under a coating.

Left unrepaired, even a fine crack can telegraph through a thin coating as a visible line. Repairing it first gives a smoother, more uniform finished floor.

Moving and Structural Cracks

Some cracks keep moving, opening and closing with temperature or ground movement. A rigid filler in a moving crack will often break loose again, so we use a more flexible material or treat the crack as a joint, and we note in writing that it may reappear.

Cracks with one side higher than the other, or ones that keep widening, can point to settlement or heaving under the slab. Those are not cosmetic, and we recommend having the cause looked at before the floor is coated.

Cracks That Leak Water

In basements, a crack that weeps water is a water problem, not a floor-finish problem. A coating will not stop it, and water pushing up behind a coating will lift it. We point those cracks out and recommend dealing with the drainage or foundation issue first.

Spalls, Pitting and Scaling

Spalled Edges and Chipped Joints

Spalling is when chunks of concrete break away, often along joint edges where wheels and forklifts hit them. We saw or grind back to sound concrete, then rebuild the edge with a repair mortar shaped to match the surrounding floor.

On commercial floors, rebuilt joint edges are usually paired with a semi-rigid joint filler. That supports the edges against traffic and keeps them from breaking down again.

Freeze-Thaw Scaling in Garages

Garage slabs here take a beating from brine and rock salt that ride in on tires from November through March. That salty water soaks into the surface, freezes and expands, and over time the top layer flakes off in patches. The worst damage is usually just inside the overhead door.

We grind scaled areas back to firm concrete and resurface them with a repair mortar before coating. A coating then keeps future brine on top of the slab instead of letting it back in.

Pitting and Popouts

Small craters from popouts, worn aggregate and old damage are filled with a patching compound and ground flush. Filled properly, they no longer collect dirt and water and they vanish under the finished floor.

Joints, Patches and Old Repairs

Control and Construction Joints

Control joints are cut to give a slab a place to crack neatly. When coating, we either fill and coat over them or keep them open and honor them with a flexible sealant, depending on whether the slab is still moving at those joints.

Previous Patches

Older floors often have patches from past plumbing, drain or slab work. Some are sound; others are crumbling or poorly bonded. We test each patch and remove and replace any that are loose, because a coating over a weak patch will fail at that spot.

Many of Waterloo’s older homes have basement and garage slabs patched several times over the decades. Sorting the good patches from the failing ones is a normal part of preparing those floors.

When Replacement Beats Repair

Heaved, Sunk or Broken Slabs

A slab that has lifted, dropped or broken into loose pieces cannot be fixed with filler. Settlement and frost heave move the concrete itself, and coating over it only covers the symptom.

In those cases we recommend replacing the affected section first. We then grind, test and coat the new and old concrete together once the new slab has cured enough to accept a coating.

New concrete holds a lot of water from the pour and needs time to release it. We test the new section for moisture before coating it, and if it is not ready, we schedule the coating for later rather than trap that water under the finish.

Deciding What Is Worth Saving

The decision between repair and replacement comes down to cost, appearance and how long the floor needs to last. A garage slab with a few cracks and a scaled patch near the door is almost always worth repairing; one with large heaved sections and broken pieces is usually not.

We put our recommendation in writing with the reasons, so you can compare it against a concrete contractor’s quote for replacement and decide with the full picture. Each reason is tied to something we found on the slab, not left as a verbal opinion.

Materials We Use for Concrete Repair

Rigid Fillers and Epoxy Mortars

Dormant cracks, pits and small spalls are filled with rigid epoxy or polyurea crack fillers and epoxy mortars that bond tightly to the surrounding concrete. They cure hard enough to grind flush, so the repair sits level with the slab and does not telegraph through the finished coating.

Flexible Sealants and Joint Fillers

Where a crack or joint is still moving, a rigid filler will simply crack again beside the repair. Semi-rigid joint fillers and flexible sealants are used there instead, chosen for the traffic the floor carries, from car tires in a garage to forklift wheels in a warehouse.

Cementitious Repair Mortars

Larger scaled areas and rebuilt edges are often resurfaced with polymer-modified cementitious repair mortars. These are troweled to shape, allowed to cure, and then ground and profiled like the rest of the slab before the coating system goes down.

  • 20+ Years Coating Concrete
  • Moisture Test in Every Scope
  • Free Written Estimates

Good to know

Frequently Asked Questions

Can every cracked concrete floor be repaired?

Most hairline and shrinkage cracks can be repaired and coated over. A slab that has heaved, settled unevenly, or broken into loose pieces usually needs that section replaced, and we tell you so instead of patching over a structural problem.

Will repaired cracks show through a new coating?

A dormant crack that is properly routed, filled and ground flush usually disappears under the coating. A crack that is still moving may reappear as a hairline over time, so we note moving cracks in writing before the job starts.

What causes the pitting near my garage door?

Usually freeze-thaw damage: salt brine from tires soaks into the concrete, freezes and expands, and pops off the surface in flakes and pits. We grind back to sound concrete and rebuild the area with a repair mortar before coating.

Do you repair floors without coating them afterward?

Yes, though most repairs are done as part of a coating or polishing job. Repairs left exposed are more visible and will weather differently from the surrounding slab, which we explain before starting.

Can you fix a crack that leaks water into my basement?

A crack that is actively weeping water is a drainage or foundation issue first. We can note it and recommend having it addressed, but filling it from the top and coating over it will not stop the water and may lead to the coating failing.

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