How to Repair Cracks in Concrete Foundation Wall?

Repairing Cracks in Concrete Foundation Wall

Foundation wall cracks are an eyesore! Let me explain to you How to Repair Cracks in Concrete Foundation Walls in the easiest way possible.

Not only will I highlight wall repair methods, but also make sure that you learn How to Fix Foundation Cracks in Basement as well.

Concrete is an extraordinarily strong and super versatile construction material.

Yet, many of you might be thinking to yourself:

Why is it prone to cracks?

In reality, it can crack for several different reasons, including moisture, temperature changes and ground movement.

These cracks can either be a cosmetic problem or they may indicate a more serious structural issue. Whatever be the case, this article will help you repair a cracked wall in just 2 days!

6 Steps Towards an Easy Crack Repair:

To do this:

You will require the following 8 Tools and Supplies:

  • Chisel
  • Drill
  • Water
  • Sponge
  • Acrylic Bonding Agent
  • Trowel
  • Air Compressor

Follow these 6 quick and easy steps to learn about Vertical Foundation Crack Repair.

Step 1: Clean the Crack:

The first thing we need to do is, clean out the crack of any debris. We do this by losing it up with a screwdriver or a chisel. The main idea is to use something that can get down in there.

Once you loosen it up, you can suck out the debris with the shot back or blow it out with an air compressor.

Step 2: Fill the void with Triple Expanding Foam:

Once cleaned, we fill the gap in the block with some triple expanding foam. A triple expanding foam is a weather-resistant bond formulated to seal out hollow spaces around the home. This foam comes in a can with a nozzle for precise application.

But how do we use this foam?

What you do is, take the can and hold it upside down. Stick the nozzle inside the void. Start filling from the center because it will scale up and spread drastically. Spray the desired amount and let it set.

Step 3: Remove excess foam:

After about 5 or 10 minutes you will be able to see the foam really expanding out. So much so, that the foam will be sticking out of the wall. We are going to let it dry and carefully chisel the excess out.

What will be the right consistency of the foam before we chisel it out?

By and large, its texture will be dry on the surface, but soft on the inside. That is when we take a trowel and shave it off.

Now that the foam is still a little bit soft, we push it back into the hole to make room for our mortar.

Step 4: Prepare the Crack for the Mortar Filling:

Next, we make room for the mortar. In order to do so, we expand the crack using a chisel further down towards the very end of the slit to make it look bigger. We make the crack wider so that the mortar does not fall out. Just make sure you clean it all out.


Do not scrape too deep into the cracks.

Step 5: Prepare the Mortar Mix:

Note that:

You will require assistance for this step.

Ask someone to hold the drill for you so that you can add mortar mix to the water. Now, add some acrylic bonding agent to the mix. It will help make the mortar stick to the wall even better.

Once mixed, let it set for a few minutes and then start putting it on the wall.

Pro Tip:

It is always a good idea to wet the surface before you put the mortar on it. Since the wall is naturally dry, it will suck all the water out of the mortar causing the mortar to crack.

Step 6: Fill the Mortar Mixture in the Cracks:

Without delay, we are going to take the mortar out of the bucket and push it into the wall. The foam is nice and hard, which is good, because it provides a base for the mortar to sit.

After that, smooth out the mortar application using a small rectangular trowel. Scrape off the excess and make it flat.

Now, add some texture to it to match the wall.

How do I add texture to my newly repaired wall?

To do this:

  1. Take a sponge with some water and wring it. You do not want it to be too wet.
  2. Simply skim the sponge right over the wall lightly.
  3. As soon as you are done skimming, you will see the grit rising, giving a little bit of texture to the wall. Now it matches the wall around it.
  4. You can very well paint over it after a couple of days.

DIY Foundation Crack Repair – Do it at Home!

Get ready to hack into some tips and tricks regarding foundation crack repair using items present at home or readily available in the market.

We now know that:

These cracks can be either structural or non-structural, dry or wet and leaking. For all these conditions, concrete crack injection technique is the best.

How does a concrete crack injection process work?

This injection process is fairly simple.

Here is how it works:

  1. Firstly, surface ports are bonded 6 to 10 inches apart along the crack of the wall that is being repaired.
  2. Secondly, the crack is sealed with a surface
  3. The product, Polyurethane foam, is then injected through the attached surface ports starting at the lowest port.
  4. As the product is injected, it flows through the crack to the outside of the wall, filling the crack.
  5. The product then encounters the soil behind the wall, eventually forcing itself up the crack. This is the path of least resistance. From here it goes to the next surface port.
  6. As injection continues, the product will fill any voids behind the crack.
  7. Repeat the process along the entire length of the crack.

Crack in Foundation Slab – Repair in Just 24 Hours!

A crack in the foundation slab can be full of dust and debris.

When in need of repair:

  1. Clean the entire length of the crack.
  2. Next, use some backer rod to press down into the crack. Backer rod is the round foam which is available in several different diameters. It is going to allow us to fill the crack without having to use a lot of expensive filler.
  3. Later, press it down into the crack.
  4. Then, you will need a liquid crack filler. It is highly elastic, self levelling and ready-mixed.
  5. Apply enough, so that you slightly overfill the crack to allow for some settling all the way down the crack.
  6. You can use a wet finger to smooth it out after this sets up.

No wonder, it is a super quick fix as it will take a maximum of 24 hours for it to set. Hence, you do not have to wait a long time before you walk on it!


  • Make sure you are working in a well-ventilated area.
  • Wear a mask before starting off with this project.

Cracks in Basement Walls, When to Worry?

Though these cracks may look scary, they are never beyond repair. However, if you leave them unattended, they can get worse with time.

In the long run, it is common to forget about the maintenance of these cracks. You may not even notice them getting bigger.

As a result, the foundation cracks grow, and the entire foundation may collapse!

Given that, the construction business is not getting any cheaper, this will cost you an arm and a leg. So, it is always better to fix now rather than later.

How to Repair Concrete Foundation Crumbling?

Right now, I am going to tell you how to tackle a crumbling concrete foundation in case you have something similar going on around your house.

It is pretty simple:

Here, we will need cosmetic touch up.

We are going to need:

  • A stiff brush also known as a wallpaper brush.
  • A sandpaper.
  • Pressure washer.

Let me tell you how to tackle with this:

  1. We use a stiff brush to crumble off as much as possible.
  2. Next, scrape the paint using sandpaper. We do this, because we do not want to put the new cement mixture on top of the paint.
  3. Finally, use a pressure washer to get rid of excess paint. We let it dry a little.

This will ultimately bring back the integrity of the concrete foundation.


As has been noted, sealing the non-structural cracks in concrete foundation is an easy project to complete for any skill level. In this article, how to repair cracks in concrete foundation wall? we learnt that; as with any concrete repair, proper tools for crack preparation is essential to achieve a successful result.