How To Fix Cracks on Garage Floors

Knowing how to fix cracks on garage floors will help you improve the appearance of your floor and garage in general.

How To Fix Cracks on Garage Floors

Garage floors are made with concrete. Concrete is a very strong construction material prone to cracks for various reasons such as moisture, temperature changes and ground movement.

Cracks are thin, long cuts breaking the concrete apart. Some cracking is unavoidable as floors gets old particularly in areas of severe heat thaw cycles. In newer concrete floors, cracks can be as a result of poor construction or overload.

These cracks cause dust.

How To Fix Wide Cracks On Garage Concrete Floors

  • First thing to do is to cleanup the crack, open it up with something like a screw driver or chisel and blue it out with an air heater.

The cleaner the crack is the better.

  • Fill the crack with a backer rod if it’s deep.
  • Next, use a liquid crack filler to fill the crack. 
  • Fill the crack very well to allow it settle well and use something to smooth it out.
  • Allow it to set for about 30mins – 24hours.

It’s super quick and you don’t have to wait for a long time before walking on it.

  • If you wish you can also grind down the filler so that it becomes more even with the ground; to do this you can use a diamond tube cup wheel attach to an angle grinder.

How To Fix Small Cracks On Garage Concrete Floors

  • For a small crack, use a crack chasing blade on an angle grinder to make the crack open up
  • Then properly clean the crack
  • Apply liquid crack filler to it
  • Level it out using angle grinder

How To Fix Cracks In Garage Using Concrete Patching

Garage floors are made with concrete, so you can fix any crack on it with concrete vinyl patching compound, and it’s quite easy to find and use.

Here is a step to step way of fixing any kind of crack on your garage floor using concrete patching method.

  • Clean out the crack to get rid of any debris or loose chunks, you can do this using a screw driver or chisel.
  • Use a wire brush to get rid of dirt that has accumulated in the crack over time.
  • Clean the surface area of the crack to help the new patch stick to the old concrete
  • Apply a concrete cleaning products such as Zep’s Driveway and concrete pressure wash concentrate or any other products to the crack, use the product to thoroughly clean the crack.
  • Allow the crack to dry before you apply appropriate amount of a concrete vinyl patching compound

How To Prepare The Concrete Vinyl Patching Mix

  • Add a small amount of water to the powdered mixture.
  • Mix it until you have a not so sticky consistency.
  • Then apply it with a trowel to the crack.
  • Use the back of the trowel to smoothen or level out the area to match the existing concrete floor.
  • Allow the compound to set for about 20minutes or more, then use a grounding sponge and water to clean out any excess patching compound from around the patched area to create a seamless patch.
  • Apply several layers of the patching compound to fill the void on a wider or larger cracks.

How To Fix Your Garage Floor Using Polymerized Concrete 

Polymerized concrete is cement mixed with special aggregate material that allows it to adhere to existing concrete.

Polymerized concrete comes in powder form that you mix with water. Unlike epoxy it takes longer time to cure, so you can mix a large quantity at once. 

Remember to follow the instructions of the manufacturer while using it.

To use polymerized concrete to fix cracks in your garage floor, simply follow the same steps for using vinyl patch compound and replace the vinyl patch compound with polymerized concrete.

How To Fix Crack Concrete Slab

Some garage floors are made with concrete slabs. Concrete slabs are structural elements, usually horizontal, used to construct flat surfaces for floors, roofs and bridge. They are supported by beams, walls, columns and grounds. 

Step By Step Process Of Repairing Cracks On Concrete Slabs

  • Get a crack sealant product
  • Use a wire brush to clean out the crack and the surface of the crack.
  • Shake the crack sealant very well, just in case it has been sitting on the shelf for a long time. Then apply it into the crack and leave enough on top. This way, when it settles down into the crack it will be enough. 
  • Allow it to set or harden for around 24hours or even more.
  • Then use a sandy equipment like a rigid multi-tool and a diamond grit sandpaper to sandy it down so that it’s even with the surface of the concrete
  • Lastly, brush the dust away. 

Why Do Garage Floors Crack?

Garage concrete floors cracks are not a cause for alarm, it’s a common thing, it’s just a cosmetic thing. All concrete floors crack regardless of whether they are outside or inside. Concrete floor outside has control joints which controls where cracks happen on the floor, garage floors don’t have these control lines or joints. 

It’s a normal to see cracks on garage floors, don’t be alarmed, garage floors are made with concrete so it is bound to crack, that’s just how it is.

Here we are going to look at a number of reasons why garage floors crack.

  • Moisture – Some cracks happen because there is water underneath the floor.
  • Shrinkage – New garage concrete floor cracks because it shrinks and contrast as it hardens. Shrinkage is one of the major causes of cracking on garage floor, as the concrete floor hardens the volume of the concrete gradually decreases and if the component is restrained against free movement, tensile stresses are developed which causes cracks.
  • Temperature Fluctuation – Changes in the temperature of the garage affects the concrete floor and results in differential volume change. When the tensile stress capacity of the concrete exceeds due to the differential volume change, it will crack.
  • Chemical Reaction – Concrete are made with cement which is alkaline in nature. The alkaline reacts with the carbon dioxide(CO2), present in the atmosphere resulting in an appreciable increase in the volume of materials which finally causes the garage concrete floor to crack.
  • Poor Construction Practices – Poor construction practices such as adding excessive water to the mix, lack of curing, poor compaction, using low grade materials like poor grade of cement, unreasonable placements of construction joints among others, can cause the garage concrete floor to crack.
  • Wrong Structural Design – Errors in design and detailing such as inadequate amount of reinforcement, improper design of foundation, precast members and slabs, improper selection of materials, lack of sufficient construction joints etc, may result in cracking on the garage concrete floor.
  • Construction Overload – The load induced in the structure during construction can also lead to cracking especially at the younger stage when the for work is removed early. Early opening of formwork from slabs causes cracks.
  • Elastic Deformation and Creep – Like the different components of a building, the garage concrete floor undergoes elastic deformation when loaded. This unusual deformation results in cracks in garage concrete floor.
  • Corrosion of Concrete – Cement which is used for concrete flooring contains steel and the corrosion of this steel develops a huge amount of Iron oxides and hydroxide that have a much greater than the volume of metallic iron, hence, the volume increases and cracks.
  • Insufficient concrete cover for reinforcement. Use more concrete on sea areas and less concrete in dry areas.

How To Fix Cracks on Your Garage Epoxy Floor

Epoxy is very safe coating for floors such as the garage concrete floors. Yes, some garage floors are coated with epoxy. Epoxy-coated floors look good and are easy to clean and maintain.

Epoxy is made up of resin and hardener, which are mixed together either in a self mixing nozzle or on any disposable surface. 

This mixture cures into a hard, sand-able and paintable material. Epoxy cures very fast, so you need to mix it little by little.

Epoxy is not absorbent and resists oils and road salts.

To make epoxy look like concrete, just mix it with aggregate materials. 

While using epoxy, ensure you follow the manufacturer’s directions.

Here are simple steps to take to repair any crack on your garage epoxy floor;

For Minor Cracks

  • Clean out the crack properly and remove any dirt that might have accumulated in it.
  • Get a vinyl patching compound, mix the powdered with water and use it to fill the crack. Smoothen the surface with a trowel or whatever you used to apply the mixture
  • Remove excess patches and allow the mixture to set and harden for some day.
  • Then apply a new coat of epoxy

For Large Cracks

If the crack is large, then patching it like in the case of minor crack won’t be wise. It’s better to resurface it. And here is just how to do that.

  • Sweep the area
  • Get rid of all oil on the surface by cleaning the area with a grease cutting detergent.
  • Patch any hole in the floor with an epoxy patching compound
  • Let it cure for some days 
  • Sweep and clean the floor again to remove any dirt, dust or oil.
  • Apply a new coat of epoxy to your floor. First apply epoxy paint, allow it to dry before applying epoxy finish.

When Should I be Worried About Cracks on My Garage Floor?

Most cracks on the garage floor are normal and nothing to worry about however some are not. Some cracks are indicators that something is seriously wrong and needs professional attention.

The common cracks on garage floors are cosmetic-caused cracks while the more serious cracks are structurally-caused cracks. 

Structurally-caused cracks are an indicator that something is wrong with the foundation of the garage.

Below are signs of structurally-caused cracks, if you notice any of this signs in your garage, then you need a professional to look at it.

  • You need a professional when you notice that the crack is rising out of the floor, as this shows that the foundation has shifted and contracted a little, pushing up the raised area. 
  • Erosion of the floor is another sign that there’s a deeper structural issue.
  • Uneven cracks surface. When one side of the crack surface is higher than the other, it’s likely to be a structural issue. 

Structurally-caused cracks does not just affect the floor but also the whole building.

Check for the following in the building when you suspect that the cracks are structurally-caused:

  • Sloping floors
  • Cracks on the garage walls
  • Sagging roof
  • Difficult to open and close doors and windows.

How To Prevent Cracks on Garage Floor

There is no way to entirely prevent cracks on garage floors, but there are some ways to limit the cracks.

Here are some of the things you can do during and after the concrete pour to limit the occurrence of cracks on the garage floor.

  • While constructing the concrete floor put rebar or wire in strategic places, this reduces cracks on concrete floors.
  • It’s best to do your concrete flooring in a cool season rather than a hot season, as the heat dries up the water in the concrete faster and leave your concrete floors all cracked up.
  • Use more concrete in sea areas and less concrete in dry areas. This will help prevent water from the ground from easily penetrating through the concrete.
  • Use a post tension slab. Though this can be quite expensive.
  • Install a temperature regulator in your garage
  • There should be enough construction joint
  • The right grade of cement should be use for the construction of garage concrete floor.
  • Ensure that the cement and water are properly mixed together.
  • Add epoxy to your garage floors 
  • Poor construction practices such as poor compaction and lack of curing that can cause concrete garage floors to crack should be avoided.
  • Install control joints, this helps to control where cracks happen.

How To Maintain Your Concrete Garage Floor

Maintenance is very crucial for anything to last long. Your concrete garage floors need maintenance in order to last longer.

Concrete floors are very easy to maintain. 

These are ways to maintain your concrete garage floor

  • If possible, dry-mop daily to get rid of dirt and debris
  • From time to time, maybe twice a month make out time and thoroughly sweep  your concrete garage floor clean this is the easiest way of maintaining it.
  • Get rid of every rust stain, oil stain and any other stain as soon as it happens. You can get rid of these stains using warm water and a detergent or degreaser.
  • Clean out every crack before filling it.
  • Add a concrete sealer to your garage floors
  • You can also apply a floor wax.

How To Maintain Your Epoxy Garage Floor

Here are some of the things, you need to do to maintain your epoxy garage floor

  • Use a broom with soft bristles to sweep your floor on a daily basis 
  • Mop the floor at least once every week
  • Get rid of every spill as soon as it transpires. 
  • Keep scratching objects away from your epoxy coated garage floor
  • Ensure that your epoxy surface are always dirt free


Cracks in garage floors are very common and hardly a course for alarm.

It’s very easy to fix a crack. There are different kinds of cracks, and each type of crack has a way to fix it and get it looking all new again.

You can fix cracks on your garage floors by yourself, but there are cases when you will need a professional to take a look at the cracks. Especially when the cracks show signs of  foundational faults.

There are a number of things to do, during and after concrete pour, to maintain it and minimize the chances of cracks from occurring.

One of the things to do, is to coat your concrete garage floor with epoxy finish or seal it with any other sealant.

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