Concrete Crack Repairing: How To Repair Small and Large Concrete Cracks

Occasionally, homeowners need to undertake repairing of concrete cracks that tend to develop on driveway, sidewalk or walls from time to time. Here you’ll know ways to repair those cracks but first let us see what causes these cracks to appear.

What Causes Concrete Cracks

There are quite a few factors responsible for causing cracks in different parts of house. At times these may be caused due growth of unwanted vegetation close to foundation or it may be due climatic conditions. However, the most frequent cause for formation of cracks is stagnant water. If drainage is inadequate or improper, water would generally find its way down among weakened sections and create a crack. It is therefore imperative to resolve drainage problem beforehand otherwise the cracks are most likely to reappear.

Related: What is the difference between Concrete and Cement?

Repairing Concrete Cracks

There are various options available for repairing cracks. The technique and material to be used depends on how small or big the crack is. Nevertheless, one common element for repairing all kinds of cracks is cleaning and preparing the crack before filling it up with an appropriate material.

Preparing the Surface

clean concrete crack
clean the crack

It is vital to clean and wash the affected area before filling the concrete crack with appropriate material.  It is imperative to remove any oil or grease from the surface. This may be a bit difficult when trying   repairing part of concrete which has been used for parking car or the one in your kitchen but you must ensure that it is clean before you add proper repair solution. Unless it is properly cleaned, the concrete repair kit does not stick to the crack. You should also wash away any previous attempts to repair the concrete cracks, like previous sealers, hardeners, or coatings. Use a blast cleaner to get rid of these as they will affect the sticking power of the material used for repairing concrete cracks.

Small Cracks

Small concrete cracks that are about 3mm wide can be repaired very conveniently. Using a screwdriver, you need to get rid of loose concrete and flakes. Next, clean the affected area with a wire brush and make the crack free of dirt and debris. Finally, rinse the area with water.

small concrete crack
concrete thermal cracks

Prepare small batch of concrete patching compound that is available at most hardware stores.  Use of latex additive allows the compound to expand naturally through cold and hot weather. With help of a small putty knife, trowel the compound into the concrete crack and smoothen the surface right then when the compound is still damp as such compounds usually begin to set very fast. Let the surface get dried completely before allowing anyone to drive over it.

Cement Paint

Small concrete cracks can also be repaired with cement paint. No, it’s not paint really but as easy to use as paint. In fact, it is diluted cement mixture that can be applied on the crack with help of a brush. This is most suitable for hairline or thin and small cracks and is the easiest way to repair such cracks.

Large Cracks

large concrete cracks for repairing
large cracks in concrete

The initial few steps for repairing large concrete cracks are the same as in case of smaller cracks. So, you’ll need to remove loose concrete and flakes, clean the crack with a wire brush and rinse the cleaned part with water. Here are the two ways to fill that crack:

Caulking method: Procure silicone based latex concrete caulk available at hardware stores.  With help of a caulking gun thoroughly fill up the concrete crack with caulk. The caulk expands and fills up the crack. The composition of this compound is such that it contracts or expands as per weather changes thus reducing the frequency of repairs in future.  This compound gets leveled on its own, meaning you won’t need to smoothen the surface. However, for larger cracks, multiple applications may be necessary.

Sand packing method: If you opt for this method of repairing cracks on concrete, you’ll need sand plus concrete patching compound, if possible the one with added latex for flexibility.  First fill the concrete crack with sand and follow it up with application of patching compound with a trowel. Smoothen the surface quickly and push the new surface into the existing edges to get a finished look.


You should contact to a professional in case of excessive damage.

In case of serious and unusually large cracks, it is best to hire the services of a professional.  This is particularly recommended on noticing cracks in the foundation of your home.  A professional will conduct a risk assessment survey to check if there is any structural damage. They can also assess the cause of concrete cracks and take steps necessary for avoiding such damages in future.

 It is in the interest of the homeowner to carry repairs immediately on noticing any cracks on concrete. You would agree that cracks are easier to repair when these are small. Moreover, cracked concrete doesn’t make for an attractive property. Another reason for recommending immediate action is the safety of the property and its occupants.

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