While concrete is a tough material, it does have its limitations. Over the course of several years, extreme temperatures and other conditions can cause it to warp, crack, degrade, and chip away.
Because of that, you might notice that your relatively new driveway already has some cracks in it. Fear not, because today we are here to help you learn how to fix cracks in concrete. We will cover four methods that will help you deal with cracks of all sizes
Before You Start: Preparing the Crack
First, let’s take a look at the preparation work necessary before doing the actual fixing. For all but the last method that I will mention later in this article, the preparation process is all the same.
Namely, it consists of the three steps below.
Step 1: Removing Chunks
What you never want to do when filling cracks in concrete is to just pour the filler in there. That won’t work. If there is a crack in the concrete, chances are that there are some loose pieces and chunks. You don’t want those loose chunks in there when you go repair the crack.
Therefore, you need to use a hammer and a chisel to remove any such chunks that may get in the way, as the chunks will reduce the integrity of your fix if they are left in the crack.
Chisel all chunks away and remove them as best you can.
Step 2: Power Wash
You do want to remove as much dirt and debris from the crack as humanly possible too. The less debris is present in the cracked concrete, the more successful your fix job will be.
Therefore, if possible, you should use a pressure washer to wash out the crack. Use a high-pressure model to blast any and all dirt, rocks, and concrete chunks out of the crack.
This may not be 100% necessary, but it will lead to a much better end result.
Also, if you do not have a pressure washer, at least do so using a regular hose.
Step 3: Let It Dry
If you have power washed it with a pressure washer, you need to let everything dry before moving on. If there is excess moisture present in the cracked concrete, whatever filler you use may not hold, and the whole process will be for nothing.
Now, you can move onto the actual methods of fixing a crack in the concrete.
How to Fix Cracks in Concrete: 4 Best Methods
There are four main methods at your disposal which you can use to fix cracks in concrete.
These include using simple concrete glue, filling the crack with more concrete, using expanding foam, and even starting from scratch.
Best for Very Small Hairline Cracks: Concrete Glue
For very small cracks that are not too serious, you can try using something simple like concrete glue or cement glue – some form of a concrete crack filler.
This substance is otherwise known as liquid cement or liquid concrete. It’s almost like super glue, except when it dries, it turns into concrete.
Remember that it comes in small bottles and is really only ideal for very small repair jobs.
If this sounds right to you, once the crack has been properly prepared, fill it using the cement or concrete glue. You then need to let it dry and cure according to the instructions on the specific product you chose to purchase.
Best for Large Cracks: Filling with Concrete
If you see multiple cracks or some very large cracks, I’d recommend using this particular method to repair them. Here, you actually want to mix a new batch of concrete, and simply fill the cracks with that.
Beware that this method does not work for very small cracks, as concrete is fairly thick and may not penetrate all the way down in tight spaces.
Moreover, make sure that the crack has very rough edges, as this will allow the new concrete being used for the repair to easily bond with the old concrete that is still present.
Trying to fill a crack in concrete when everything is completely smooth will likely lead to the new and old concrete not bonding properly, which will then quickly lead to new cracks forming. As such, you might even want to break the edges of the crack with a chisel before starting the job.
For more details, check my article about pouring concrete over concrete.
Best for Deep and Hard to Reach Cracks: Expanding Foam
As you can probably tell by the name of it, this material is designed to expand, just like insulation foam for walls.
When using polyurethane foam for concrete repairs, it will usually come in the form of a special concrete repair kit.
Always be sure to follow all of the directions on the label of the particular product you purchased.
When using expanding foam, be sure to put the dispenser nozzle as deep into the crack as possible, and then work your way to the exterior. If you want it to look nice, you can then sand it down and paint over it.
Best for Excessively Damaged Concrete: Start from Scratch
This is for those extreme cases where fixing a crack may not be possible. In other words, the crack is so large or severe that you actually need to replace a whole slab of concrete, rather than doing a simple fix.
Here, you will want to follow the classic method for mixing and pouring concrete.
First off, you will need either a jackhammer or a sledgehammer to pound out any old concrete. Be sure to remove all sections that have cracks in them. If those sections are fairly small, you can also use an angle grinder.
Then, as discussed in the first section on preparing the crack, you also want to remove as much debris as possible.
Now, you will need to measure the space which you are looking to fill with concrete. Once you know what the volume of the space is, you can then make your calculations for how much concrete you need to buy. Using a bucket or wheelbarrow, some water, and a mixing tool, mix the concrete and get it to the right consistency.
Pour the concrete into the space as required, and then use a concrete trowel to flatten and smoothen the surface. Let it dry, cure, and harden as indicated on the label of the specific concrete you have.
Tips & Tricks
Lastly, here are some more tips to make sure your job goes smoothly:
- Whenever working with concrete, always wear gloves, closed-toe shoes, and long sleeves. Concrete can be very corrosive when wet, and if you get it on your skin, it will burn.
- Concrete dust is poisonous. Therefore you need to wear a facial mask to prevent the inhalation of the dust.
- You also need to protect your eyes. Flying chunks can take out an eye and concrete dust can really burn if it gets in your eyes.
As you can see, there are various methods for filling cracks in concrete.
Which method you go with will depend on the size and severity of the crack, as well as how far you are willing to go to repair it. In any case, though, make sure to do the right preparation work before you begin fixing the crack.
That way, you can avoid having to redo the fix anytime soon.