Do Concrete Cracks Need to Be Fixed Before Coating Your Garage Floor?

Do Concrete Cracks Need to Be Fixed Before Coating Your Garage Floor?

Short answer: yes, but not all cracks are the same. Some are cosmetic hairlines. Some are structural issues that need attention before any coating goes down. Here's how to tell the difference.

Types of Cracks You'll See in Your Garage

Hairline Cracks (< 1/16")

These are the tiny spider-web cracks you see on almost every concrete slab over 5 years old. They're caused by normal concrete shrinkage as it cures.

Do they need repair? Not structurally, but a good coating system will fill and hide them completely. The primer coat flows into hairline cracks and seals them.

Control Joint Cracks

Your garage floor has those grooved lines (control joints) cut into it. Sometimes the concrete cracks along these joints — that's actually what they're designed for. The joints control WHERE the concrete cracks so it happens in a straight line.

Do they need repair? We fill control joints with flexible polyurea filler so the coating system has a smooth, continuous surface. This prevents the joint from telegraphing through your new floor.

Structural Cracks (> 1/4")

These are the ones that concern us. Wide cracks, cracks where one side is higher than the other (heaving), or cracks that are actively getting wider over time.

Do they need repair? Absolutely. These need to be properly routed, cleaned, and filled with polyurea or epoxy filler before coating. If one side is raised, it may need to be ground flush.

Spalling and Pitting

This is where the surface of the concrete is flaking, chipping, or has pockmarks. Common causes: road salt damage, freeze-thaw cycles, or concrete that was finished too early.

Do they need repair? Yes. We use cementitious patch material and/or polyurea to rebuild the surface before coating. The grinder takes care of minor pitting.

What Happens If You Coat Over Unrepaired Cracks?

Nothing good:

• The crack telegraphs through — You'll see the crack line through your new coating within weeks
• Moisture wicks up — Unrepaired cracks let ground moisture vapor through, causing bubbles, peeling, or white spots under the coating
• The crack widens — Concrete moves. If the crack isn't properly filled with flexible material, it'll crack your rigid coating right along the same line

How We Handle Crack Repair at Loud Bros

Step 1: Grind the Floor

Diamond grinding opens up hairline cracks and reveals hidden damage you can't see under the surface grime. We see the full picture before we start filling anything.

Step 2: Route Larger Cracks

For cracks wider than 1/8", we use a crack chaser blade to "V" out the crack. This gives the filler material more surface area to bond to.

Step 3: Fill with Polyurea

We use fast-curing polyurea joint and crack filler — not hardware store caulk. Polyurea is semi-flexible, so it moves with the concrete instead of cracking again.

Step 4: Grind Flush

After the filler cures (usually 15-30 minutes), we grind it flush with the surrounding concrete. The result is a perfectly smooth surface ready for coating.

Can Severely Damaged Concrete Be Coated?

In most cases, yes. We've coated floors with dozens of cracks, old paint, adhesive residue, and significant spalling. The key is proper prep. Diamond grinding and crack repair can handle almost anything.

The only situation where we might recommend against coating:

• Active water intrusion — If water is actively pushing up through the slab, you need waterproofing or drainage addressed first
• Severely heaved slabs — If sections of your floor are raised 1"+ above adjacent sections, that's a structural issue

Don't Let Cracks Stop You

Most garage floors have some level of cracking. It's completely normal and almost always repairable. The important thing is working with an installer who actually addresses the cracks instead of just coating over them.

Contact Loud Bros for a free assessmentContact Loud Bros for a free assessmenthttps://loudbrospressurewashing.com?page=contact — we'll check your concrete condition and let you know exactly what your floor needs.

Ready to Transform Your Space?

Get a free quote for your project today.