Why Does Concrete Crack and How to Fix It

Key Takeaways

• Concrete cracks due to natural shrinkage, thermal expansion, and ground movement.
• Clean all dust and loose debris out of the crack before applying any filler.
• Use a granular filler like Repair Express Cement for a perfect visual match on masonry walls and concrete stairs.
• Glue broken masonry blocks back together using a high-strength construction adhesive.

Concrete cracks look terrible and let water damage your foundation. You can fix these gaps permanently in just a few minutes with the right filler and some basic preparation. We will walk you through exactly why these gaps appear and show you the best way to get a highly professional finish.

Why Does Concrete Crack?

Concrete cracks because the material naturally shrinks as it hardens. As water evaporates from the wet mix, the slab physically reduces in size and this internal stress pulls the rigid surface apart. Extreme temperature shifts also force the material to expand and contract constantly. Ground settlement shifts the soil directly underneath the foundation, and these combined natural forces will slowly crack your driveway, paths, and retaining walls over time.

Choosing the Right Concrete Repair Filler

Matching your filler to the exact type of crack guarantees a permanent fix. You need a dedicated masonry product because standard interior plaster will simply wash away outside in the rain.

Repair Express Cement is an acrylic filler with a rough granular structure that looks exactly like real mortar. It blends perfectly into brickwork, driveways, and concrete stairs while curing rapidly without shrinking. This makes it your best choice for filling static holes and rigid gaps permanently.

You might also find loose or broken masonry blocks during your repair work. You’ll need a heavy-duty product to glue these broken pieces back together safely, so explore our full range of professional construction adhesives to find the exact grab strength you need for your wall.

How to Fix Cracked Concrete

You can repair holes and cracks in concrete stairs or brickwork in a few simple steps.

1. Clean out the gap: Brush out all the debris and use a stiff wire brush to scrub the inside of the crack. You must remove all loose dust, dirt, and chipped concrete because the filler needs a completely solid surface to grip properly.
2. Prepare the cartridge: Cut the plastic dome off the Repair Express Cement cartridge. Screw on the nozzle and slice the tip at an angle to match the exact width of your crack and avoid messy overspill.
3. Apply the filler: Load the cartridge into your caulking gun and squeeze the trigger steadily. Push the granular filler deep into the crack so it touches the bottom and both sides.
4. Smooth the surface: Wet a putty knife or a small trowel before dragging it flat across the repair. This blends the wet filler flush with the surrounding concrete and matches the original texture perfectly.
5. Let it cure: Leave the product to dry completely. You can paint over the surface after a few hours to hide the repair line completely.

Ready to repair your masonry? Use our Store Locator to find your nearest Soudal stockist and grab the right products today.

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