🚧 Noticed cracks in your walls or floors? It might look scary, but not all cracks mean trouble. Learn which ones to worry about — and how to fix the rest yourself 🔧 Full step-by-step guide in the article below!👇
Concrete is known for its strength and long-lasting durability, often standing the test of time for decades. But even this tough material isn’t immune to damage. Cracks—ranging from fine lines to deeper breaks—can eventually show up. Many people panic at the sight of these flaws, worrying their walls or floors might be on the verge of collapse. The truth? Most of the time, there’s no need to worry. Cracks don’t always mean there was an error during the pour—there are plenty of other reasons they can form.
Let’s break down what causes these cracks and explore practical, affordable ways to fix them using materials you likely already have on hand.
Why Cracks Form in Concrete
Although concrete is designed to be tough and resilient—just look at how long old buildings have lasted—it can still crack over time. Here are three main reasons why this happens:
Poor Mixing Techniques: If the concrete mix has too much water or sand, or the ingredients weren’t blended properly, the material can start to weaken even shortly after it sets. In some cases, cracks appear within the first couple of years.
Improper Curing: Concrete needs to be shielded from extreme conditions while it sets. Exposure to rain, freezing temps, or rapid drying can result in early damage.
Harsh Environmental Conditions: Places with constant freezing temperatures, excessive humidity, or unstable ground—like those near fault lines—can cause shifting in the concrete, leading to cracks.
Types of Cracks and What They Mean
Not all cracks are equally serious. Here’s how to understand what you’re dealing with:
Full-Depth Cracks in Load-Bearing Areas: If a crack runs through the entire concrete layer, especially in walls that support weight, this is a major red flag. If the structure is already shifting, repair might not be possible, and demolition may be the safest option.
Partial-Depth Cracks: These affect only part of the concrete surface. They’re repairable, and a solid fix can extend the life of the structure for many more years.
Hairline or Surface Cracks: These often appear on the plaster or top layer and aren’t a structural concern. You can usually fix these yourself with minimal tools and effort.
In general, surface-level damage is much easier to fix. You’ll usually just need a bit of filler or putty to seal things up.
Builder-Approved Repair Methods for Walls and Floors
1. Filling With Cement Mortar
Ideal for shallow or narrow cracks in concrete walls, floors, or exteriors.
Use a chisel to widen the crack slightly and remove any loose particles.
Clean the area thoroughly with a wire brush and vacuum away dust.
Mix a solution using three parts sand to one part cement. For flexibility and better bonding, add half a part of PVA glue.
Press the mixture into the crack using a trowel. If using a basic mix, mist the surface with water afterward. If you’re using a polymer-based mix, no water is needed.
If the crack reveals internal reinforcement (rebar), clean it and treat it with a rust inhibitor before applying mortar.
For deeper cracks, apply the mortar in layers, letting each one set before adding the next. You might notice some minor shrinking after it dries—just slightly overfill the gap to allow for that.
Once dry (typically after two days), you can paint over the repair or install flooring like laminate or linoleum. If you’re adding tile, wait a bit longer until the mortar is fully hardened.
2. Sealing Fine Cracks With Silicone
Tiny cracks are best handled with waterproof silicone sealant. It’s quick to apply, but a bit pricier than cement, so it’s best for narrow, low-volume repairs.
Clean out the crack completely.
Lightly dampen the area.
Apply the sealant and smooth it out.
3. Fixing Floors With Epoxy Resin
This method works well for small cracks in concrete floors.
Clean and open up the crack.
Carve small cross-grooves across the crack to insert metal staples or brackets for added strength.
Apply a primer to help the epoxy stick better.
Mix the epoxy resin according to the instructions, adding the hardener. For thicker consistency, add fine sand.
Pour it into the crack and sprinkle more sand on top.
Once cured, vacuum off the excess sand.
4. Using Expanding Foam Cord for Damp Areas
Perfect for basements, cellars, or swimming pool areas.
Open the crack and clean it thoroughly.
Place an expanding cord inside the gap, leaving about 20 mm from both the top and bottom.
Cover everything with polyurethane sealant and smooth it out.
As moisture seeps in, the cord expands and forms a waterproof barrier.
5. Patching With Gypsum-Based Filler
For light interior cracks in ceilings or walls, a standard drywall putty will do the job.
Brush out any dust or debris.
Apply a primer to prep the area.
Spread the filler into the crack.
Once it’s dry, sand it smooth, prime again, and finish with paint or wallpaper.
This simple repair is budget-friendly and surprisingly long-lasting.
Cracks in concrete might look alarming at first, but most are easy to fix if you know what you’re doing. With a bit of time and the right materials, you can restore the integrity and appearance of your walls or floors—no professional help required.
