How to Fix Hairline Cracks in Concrete Driveway? With Video Guide

What’s your plan for this weekend? Fishing, hiking, partying, or simply chilling with friends, right?

Well, there’s nothing wrong with that. But, you know the CDC advises us to stay home during this pandemic.

By the way, staying home isn’t as boring as you’re thinking. Think about reading a thriller book, binge-watching some movies, or simply cleaning your house. Isn’t it exciting?

Yeah, but cleaning doesn’t mean only indoor cleaning. Like everything else, the outdoor concrete driveway also needs some occasional maintenance.

Today, I’m going to inform you of the in-depth process of how to fix hairline cracks in concrete driveway on your own.

Let’s dive in!

What Causes Hairline Cracks in Concrete Driveways?

There’s a rumor that plastic shrinkage is the only reason for hairline cracks. But, that’s not true at all. Besides shrinkage, the paint quality or temperature fluctuations are also responsible for those cracks.

I just list out the most common reasons for those concrete fractures. For example –

  1. Temperature change

2. Bad plasterwork

3. Concrete segregation

4. Premature drying

5. Earthquakes

6. Humidity fluctuation etc.

When Should You Worry About Concrete Hairline Cracks?

The hairline crack is the thinnest crevice you might find in your concrete driveway.

How thin?

Well, the width of these cracks is less than a penny! You can measure a crack with a penny even though you don’t have a Vernier scale or something like that. At first, collect a penny and hold it between your thumb and finger. Then try to insert that penny against that crack.

Your crack could be called a hairline crack only if the penny doesn’t go through the crack. In terms of width, if the fracture width is less than 0.1 mm, then you can call it hairline crack.

You must repair that driveway breach before it becomes 5 to 15 mm. Otherwise, it will start water seeping. Be aware of that!

How to Fix Hairline Cracks in Concrete Driveway?

Repairing the hairline cracks isn’t a hard nut to crack. Actually, it’s nothing but a DIY task. It will take not more than 30 minutes to do it by yourself. But, you must equip yourself with the must-have concrete tools to fix it on your own.

Let’s check out the required tools first.

  • A stiff wire brush
  • A power washer
  • Concrete patch
  • Vacuum cleaner
  • Concrete crack filler
  • Waterproofing paint
  • A stiff chisel
  • Safety goggle
  • Protective gloves etc.

Okay! Hope that you have everything in your hand now. Let’s jump to the step-by-step process of fixing your driveway!

Step #1: Analyze the driveway

You might wonder, “what should I look at in my own driveway?! I look at that every day!”
Well, you’re completely right! But it’s better to double-check a few particular facts before proceeding to the fixing job. For example, check the cracks width, temperature, humidity, grass on the surface, probability of raining on that day, etc.

You know, the rain will create a problem with concrete drying. Thus if there’s a possibility of raining on that day, it won’t seem like a good day to opt for fixing.

Step #2: Clean the driveway

Once you are done with the inspecting, it’s time to start using your tools. Initiate the cleaning by removing the big pebbles or concrete particles. You can do it with your bare hand or using a broom.

I will suggest you use the broom. Besides removing the pebbles, the broom will remove other dirt from the road! It’s like killing two birds with one stone!

Step #3: Chisel out the crack

Take the chisel and make the crack wider. You may use a hammer to hit the chisel while widening the crack. Widen the crack will help the concrete filler to stick appropriately. You can also use an oscillating tool if required.

By the way, chiseling will make the surface a real mess for sure. Don’t get annoyed! We will clean these messes in the following step.

Step #4: Wash the driveway

Bring out the broom again and clean the chiseling mess from the surface. By the way, there will be some grime in the cracks. Just leave those for now.

Get a vacuum cleaner. Vacuuming the surface will pull out those stubborn dust from the hole. You may also use a driveway cleaner to perform this task. Once the surface looks cleaner, it’s time to wash it.

Now, get the power washer and mix detergent on it. Put the hose onto the surface and turn the washer on. You must clean that crack thoroughly to get the most out of that concrete filler.

N.B. If you notice any rust on the surface, remove those immediately by using a concrete rust remover. Otherwise, rust might arise from a problem with the concrete patch.

Step #5: Dry the crack

When the washing is done, give it around half an hour to dry up completely. You may use a dryer to speed up the drying process. But, drying with direct sunlight is highly recommended by professionals. Because the electric dryer dries only the exterior while the internal concrete remains moist.

Step #6: Inject the filler

Now, inject the concrete filler slowly into the hairline crack. Make sure that the filler fills the crack. Then, check the cracks after a few minutes. If the crack doesn’t settle, apply more until it becomes level with the original concrete surface.

However, you should look for the best concrete patch to fill the crack if the width is 10 to 15 mm. If you prefer a concrete patch over the filler, make sure about mixing it by using the manufacturer’s instruction. After the application, wipe the excess patch by using a wet rag.

Step #7: Allow it to cure

Now allow the concrete path or the filler to cure around 24 hours. The patch may get hard within 2 hours. But, it takes about a day to cure the surface completely.

After it gets cured, apply the waterproofing paint on the surface. This painting will make the concrete patch invisible as well as make it even with the surface.

The beauty of using good-quality waterproofing paint is that it dries quickly. So, you can add the second layer of the paint within a few hours. By the way, it is recommended to apply three to four layers of paint on the surface.

Check the video below to get an in-depth overview of the total fixing process.


Always wear protective gloves and safety goggles while fixing hairline cracks in concrete driveways. Besides that, follow the manufactures instructions to mix up the concrete patch or to apply the concrete filler.

How to Prevent Future Hairline Cracks in Concrete Driveway?

You know, prevention is always better than cure. As you’ve already fixed some cracks in your driveway, make sure that you don’t have to go through the same process again and again.

That’s why I have gathered some tips to prevent future concrete cracks on the surface.

  1. Cure the concrete driveway properly before using it. The surface will become ready to use overnight. However, it’s advisable to give it around a week to reach its full strength.
  2. Get a windbreaker and use that to reduce the wind velocity of the surface.
  3. If the driveway is under direct sunlight, put a sunshade sail on there. Otherwise, the surface temperature will increase. It will create a few more cracks on your driveway.
  4. Apply surface sealer at least once a year to mitigate the weathering effects.
  5. Don’t plant big trees beside the driveways. Tree roots might grow underneath the road. These roots are one of the major reasons for cracking.
  6. But if you have some trees planted beside the driveway, you should consult a professional for advice.

That’s how you can keep your concrete driveway safe from future cracks.

Last Words

Hairline cracks in the concrete driveways aren’t to get tensed. Simply follow the step-by-step guide about how to fix hairline cracks in the concrete driveway stated above. That will be enough to solve your problem.

By the way, try to follow the crack prevention tips to avoid fixing your concrete surface every year.

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