If you’ve ever heard “concrete always cracks,” that’s not just a saying—it’s a reality of how concrete behaves as it cures and as it lives outside through seasons. The good news is that cracking can often be managed and planned for. That’s where control joints come in.
What Control Joints Are (And What They’re Not)
A control joint is an intentionally placed groove or cut in the concrete. It’s designed as a natural “weak point” so the slab is more likely to crack in that planned location instead of randomly across the surface. This is especially important on flatwork like driveways, patios, and sidewalks where shrinkage and movement are expected.
- Control joints are planned locations intended to manage cracking.
- Random cracks can still happen depending on conditions.
- Joint layout is part of the craftsmanship and planning of the project.
Why Concrete Cracks in the First Place
Concrete is a natural material that changes over time. As it cures, it shrinks slightly. After it’s installed, it also expands and contracts with temperature swings—especially in Northeast Ohio where freeze/thaw cycles and moisture changes can be intense.
Cracking can be influenced by many factors, including base conditions, drainage, slab thickness, reinforcement choices, and weather during and after placement. Even with good planning, concrete may crack—because movement is normal.
Will Concrete Crack Only at the Joints?
Not always. Control joints are structurally placed as the preferred location for cracking, but concrete doesn’t follow rules 100% of the time. Depending on the project and site conditions, cracking can occur outside of joints. This does not automatically mean the concrete “failed,” but it does mean the details matter when evaluating workmanship.
- Concrete may crack outside joints due to natural movement and environmental exposure.
- Drainage and base stability can affect where stress shows up.
- Joint spacing and layout can influence crack behavior.
What Quality Workmanship Looks Like
Homeowners don’t need to memorize technical specs to spot thoughtful work. In general, quality planning shows up as a clean layout, intentional joint placement, consistent finishing, and attention to practical details like how water moves around the slab.
- Joint pattern that looks intentional (not random) and fits the slab shape.
- Clean finishing and consistent surface texture.
- Proper planning for slope/drainage where applicable.
- Clear expectations discussed during the estimate (especially for NE Ohio conditions).
Frequently Asked Questions
Are cracks in concrete normal?
Concrete can crack as it cures and with seasonal movement. Many small cracks are common, but the location, width, and pattern matter. If you’re unsure, the best next step is an in-person evaluation.
What is a control joint and why is it there?
A control joint is a planned groove/cut intended to guide where concrete is most likely to crack. It doesn’t eliminate cracking—it's a way to manage it so the slab looks cleaner and performs as expected over time.
Will concrete always crack only at the control joints?
Not always. Joints encourage cracking in a planned location, but concrete may crack elsewhere depending on base conditions, drainage, weather, thickness, reinforcement, and natural material movement.
When should I be concerned about a crack?
Concerns depend on factors like width, displacement (one side higher than the other), or patterns that suggest movement below the slab. If anything looks unusual, it’s best to have it reviewed on-site.