4 Steps to Better Concrete with Injection

We’ve all heard the saying: step on a crack, break your mother’s back. What if we could adequately fix cracked concrete so it was more resilient than it ever was before? That saying might become completely obsolete! 

Cracked concrete is an annoyance to everyone. Home-owners, business owners, and city wanderers alike all at some point or another have come into contact with cracked concrete. When using the crack injection method, some cracks can be fixed and even made better and stronger than before they cracked.

Why Does Concrete Crack?

There are many reasons cracked concrete suddenly becomes an issue. Knowing why your crack happened is the first step to adequately fixing it so it will last. 

  1. Concrete poured with too much water.
  2. The slab dried too fast.
  3. The wrong strength mix. 
  4. Insufficient ground preparation before pouring the mixture 
  5. Something weighty was laid over the concrete
  6. Temperature expansion or shrinkage

All these reasons and more can lead to your cracked concrete situation. Sometimes it’s something that could have been preventable, and sometimes it’s simply the circumstance (weather, temperature, weight laid on the concrete and so on). 

concrete crack

Types of Cracks

To know what method will best fix your concrete, first, you need to identify what kind of crack you have. Identifying cracked concrete will save you time and money so pay attention to what you observe. 

  • Hairline cracks: These are tiny cracks on the surface of the concrete. They can widen over time, creating hazards, areas for vegetation to grow through or worsen the quality of your concrete.
  • Shrinkage Cracks: these types of cracked concrete issues happen when the concrete is drying. While the substance is in its plastic state, the water leaves the mixture, sometimes leaving gaps. Once the concrete solidifies, these gaps are left and create cracks straight through. You can fix this issue by keeping an eye on the temperature, water content and using control joints.
  • Expansion Cracks: Just like you learned in science class, where there’s heat, there’s expansion, much like when a door suddenly fits tighter in its jam on a hot day. Cracked concrete, in this instance, is caused by the concrete expanding against another hard surface, creating a significant amount of pressure. 
  • Heaving and Settling Cracks: these cracks happen because the ground underneath the concrete is sinking or has been frozen and built up with ice. The earth beneath the concrete sinking or the earth freezing up both cause cracked concrete.
  • Structural Cracks: may be caused by overloading the concrete (putting something too heavy on it for the particular mixture). Structural cracks that go deep are hazardous and should be taken care of immediately. 
Fixing Your Cracked Concrete

Given how your concrete can become cracked, it is best to prepare with a dependable fix. Even if a part of cracked concrete isn’t giving you trouble now (trouble being causing hazards, leaks, structural damage and so on), indeed, the crack will not repair itself. It is best to get it early and quickly to avoid a more significant job. 

Using a concrete crack injection is the primary way for hairline cracks, structural cracks and expansion cracks. If the cracked concrete is due to shrinkage or happens to be incredibly large, it’s best to call in the professionals for a proper fix. 

What is Cracked Concrete Injection?

“Cracked concrete injection” is just as it sounds: injecting the crack site with a material that will be just as durable is not more. The term ‘injection’ is that the rate at which the material fills into the crack is critical. 

If contractors fill a crack gradually, it leaves room for air pockets. Leaving air pockets behind makes the concrete susceptible to further, perhaps worse, cracks in the future. The goal of fixing your concrete, after all, is to make it just as good, if not better, than new. 

Crack Injection: Epoxy or Polyurethane?

How do you know which injection material will work best for your cracked concrete? 

The truth is, both materials will get the job done. Both bind within the crack, sealing it from front to back and require low pressure. In most cases, you can complete this at home with a crack injection kit.

Epoxy: These crack injection materials come in a wide range of consistencies, from a thick paste to a thin substance. Your choice of consistency depends on the size of the crack- for larger cracks, using a paste-like substance will offer more control. The big payoff in using epoxy mixes is the strength. Epoxy is a solid substance that can make your cracked concrete stronger in the long run when injected correctly. The drawbacks? Epoxy takes a long time to harden, leaving it susceptible to leaks if not managed correctly.

Polyurethane: Polyurethane comes in a foam-like substance. It sets quickly, reducing the possibility for leakage and further damage. Polyurethane is also a water retardant, safeguarding your project from a dreaded water issue. What are the drawbacks of polyurethane? They add zero strength resilience to your cracked concrete and are not as valuable for complete structural repair. 

There we have it. Epoxy is best for larger jobs and where added strength is needed, while polyurethane is best for small cracks that need a quick fix. 

A 4 Step Concrete Injection Process:

The process of injecting your cracked concrete is quite simple. Most folks can complete it at home if the crack is relatively manageable. 

  1. Injection port installation: Any kit will come with small plastic tubes called injection ports. They are placed over the crack and mended to it with an epoxy paste. Injection ports eliminate mess, interaction with substances and ensure the crack and only the mixture gets filled. 
  2. Seal the Ports: the ports must be sealed with the epoxy paste to do their job. They need to withstand the pressure of the injection. 
  3. Inject your Substance: beginning at the lowest port, injecting either your epoxy or polyurethane mixture into the cracks. Use consistent and slow pressure to the injection tool. Cap the port when completed. 
  4. Port Removal: after a day or two, remove the capped ports with a hammer. You could gently sand the epoxy in the area if it looks a bit messy. 

This simple 4 step process allows your cracked concrete to enjoy a longer and better life. It prevents bigger crews from having to come in and carry out repairs that might be expensive and lengthy. 

Still have questions? We’re concrete experts! Check out our blog for more helpful tips and tricks to make your concrete more robust and last longer.  


Walser Contracting Ltd.
Concrete Cutting & Coring Services
15C Alberta Ave, PO Box 3816,
Spruce Grove, AB T7X 3B1

Monday to Friday: 6:30am to 4:00

Call: 780-721-3405
Email: walserltd@gmail.com

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