Garage Floor Repair: How to Repair Cracks, Holes, and Everything else

Any garage floor will experience various amounts of wear and tear. Anyone who owns a home can expect to eventually have some cracks in your garage, holes, and other minor defects.

If you’re wanting to seal or epoxy your garage, then you’re going to need to repair the cracks first.

Fortunately, many minor garage floor repairs can be repaired by anyone willing to take the time to learn how to do it and is willing to get their hands a little dirty.

Like all DIY (Do It Yourself) projects, there is a limit as to what an individual with little or no experience can do, however many “small repairs” (meaning small cracks, holes, etc) can be done by a single person with little or no experience.

Tools to required for Garage Floor Repair

1. Sand paper 

Used to remove any large bumps but also to create a rough surface

2. Wire Brush 

Used to remove any dust and debris

3. Bucket

Used to mix and hold your wet concrete

4. Trowel

Used to mix your concrete and apply it

5. Dry Concrete Mix

The raw material required to patch your floor

6. Paper Towel or Spray Bottle (Mister)

Used to ensure your surface is slightly damp, which will ensure a more successful patch.

7. Water

Used as a vital ingredient to make concrete. This can be tap water and must be fresh water (not saltwater)

8. Plastic Bag and Broom

Used to dispose of any excess concrete

9. Positive Attitude

How to Make Minor Repairs on Your Concrete Floor

1. Prep-Work

Like anything related to concrete repairs, the most important thing to ensure the job is a success is to properly prepare the surface.

The first step is to ensure that the surface is “rough”. Having a “rough” surface will allow your existing concrete to bond to your new concrete. If your surface is too smooth, the new concrete may not stick to the old concrete and may “slide out”.

For many small projects, you might not need to do much “roughing” since the surface might already be rough enough to ensure a good bond between your old concrete and the new concrete. However, if you aren’t sure whether your existing surface is rough enough, take a piece of coarse sandpaper and rub your surface a couple of times where you wish to apply your new concrete. 

Once you have roughened up the surface, it is important to ensure it is clean and free of any loose particles like dust. Any loose particles will decrease the chance of your new concrete bonding to the old concrete. In an ideal world, a shop vac would be used to ensure that the area is free of dust and debris. However, a brush should be more than enough to ensure you achieve a surface free of debris.

If the floor is stained (from oil or other chemicals) it is important to remove these as well. Depending on the type of stain present, (oil, salt, et) you can find a suitable product to remove that particular product. Like any chemical, it is crucial that you read and follow the instructions.

2. Mixing and Pouring The Concrete

Before moving forward with the actual mixing and pouring of the concrete mix, it is important to read the instructions and ensure you have all the necessary tools. The majority of concrete mixes you will purchase use similar methods, but it is always important to double-check and ensure that you did not purchase a special concrete.

When mixing the concrete, you always want to add water to the dry concrete. Ensure you measure out your cement powder (or sometimes called “dry/bagged concrete”) and place it in your bucket. Follow the instructions to use the appropriate amount of water, obtain a good consistency, and ensure you mix everything properly and thoroughly. The look should be uniform, and you want to avoid any “clumps” of cement powder.

Once the concrete is mixed, and before you pour it, use a spray bottle or a wet paper towel to moisten the area where you will pour the concrete. Doing this will help ensure the new concrete hardens properly.

Now take the wet concrete you have mixed in your bucket, and place it into the hole or crack you wish to fill or repair. Ensure you place sufficient concrete so that the level of the new concrete is higher than the existing floor level.

3. Trowel and Level

Once the new concrete has been placed, use your trowel to level and remove any excess concrete. You want to ensure it becomes level with your existing garage floor. Depending on the size of the crack or hole you are filling, you either want to start from one side and work towards the other, or start from the middle and push towards the outside. You never want to finish trowelling in the center of your patch.

You will likely need to repeat the troweling process several times. What is important is that you repeat enough times to ensure you achieve a smooth and level surface with the existing concrete floor.

4. Clean Up

Once you have used your trowel to flatten and smoothen the concrete, remove the excess concrete you have wiped from the surface and discard it. A plastic grocery bag or garbage bag is a convenient way to hold the discarded excess material. You can also use a vacuum to remove some of the concrete that’s come loose.

5. Let The Concrete Harden

Now let the concrete harden. During the hardening process, it is important to ensure you do not place any objects overtop, and ensure that nobody walks or drives across your freshly poured concrete. In most households, nothing needs to be done to block off the space, however, if you have a large family or small children, it might be advisable to install some sort of barrier.

6. Cure

Once the concrete has been set (hardened), take a piece of wet paper towel and place it over top of the freshly poured concrete. This process is called “curing”. The amount of time you should wait before doing this can vary. What is important is that you can touch the concrete without leaving any marks. This will occur roughly 4 afters after your pour, however, you do not need to do this immediately. To ensure that the concrete is solid otherwise the damp paper towel will stick to the surface and ruin your work.

7. Admire your Work

That’s it. After a day or two, you should be able to treat your floor like you did before.

Tips And Tricks:

Preparation work is the most important part. No matter how well the concrete is mixed and how well you can use a trowel, having a poorly prepared surface will cause your repair to deteriorate quickly. So take the time to ensure it is rough and free of dust and debris.

Be patient. Wait the extra couple hours or the extra day before you return to normal. Giving your new surface that little bit of extra time will ensure longevity. 

Think of the time you spent purchasing supplies, preparing the surface, and waiting. The last thing you want is to have to redo everything because you were in a hurry and wanted to save a couple of minutes.

Clean up immediately. Wet concrete is very easy to dispose of. However, once the concrete has hardened, it is difficult to remove. Therefore ensure you remove any excess concrete from your garage floor after you trowel and smooth the surface, and ensure you clean your bucket before the leftover concrete has the chance to harden.

Keep the area moist (cure). Concrete hardens when the cement powder mixes with water. Even after you pour the concrete and it appears hard, the concrete will continue to harden for days. However, it needs water in order to do this. This is why you should moisten the crack before you add your new concrete, and use the wet paper towel after it hardens to allow it to keep hardening.

Understand that there are some problems that need to be dealt with by professionals. Sometimes a concrete crack or hole will appear, and at first glance, they may seem small. However, if you do see that your crack is caused by settling (meaning entire sections of the floor are uneven), or upheaving (where the entire surface is moving up), then this is a sign that there is a larger problem and will need to be addressed by a professional.

Final Thoughts

Repairing your garage floor is vital if you plan to seal your concrete or give it a new coating. Take the time to repair your garage floor so the end result of your hard work is something you can be proud of.

If your concrete floor is in need of major repair, you may be able to pour concrete over your existing concrete floor.

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About Roy Cohen

I'm Roy, founder of Hack My Garage. I started out like most not knowing how to hammer a nail, but now I know more than most people about home improvement and DIY. I want to spread my wealth of knowledge with the world and hope to make it a better place.