How to Fix Cracks in a Driveway

It’s a nice sunny day, the birds are chirping, and you’re brewing some fresh coffee. You walk out to the driveway to pick up the morning paper and notice new cracks. The sooner you put on the repairman hat, the better. 

This article explains how to fix cracks in a driveway before they balloon into more serious problems. 

Why is Your Driveway Cracking?

Concrete driveways can have cracks from the get-go because pouring a large concrete driveway can be tricky. Or, they develop cracks over time. Driveways typically last for more than 25 years, and it’s normal for them to develop cracks or stains from settling or everyday use.

Let’s look at a few other reasons cracks can appear in a driveway:

• Large bushes or trees can grow beneath the driveway concrete and push up the ground. 
• Parking heavy motor vehicles in the driveway for long periods can crack both asphalt and concrete driveways. 
• Repeated freeze and thaw cycles.
• Asphalt driveways can crack during the winter due to temperature fluctuations and moisture. The moisture seeps through the surface and expands when the temperature changes, causing cracks in the asphalt surface.
• Extreme heat can cause asphalt driveways to expand and crack. 
• Your driveway is more susceptible to damage if it is very old and not maintained properly.
• Scrapes and dings from edged or sharp items such as snow shovels, snowblower blades, and studded tires can crack the surface.  
• Driveways with thin asphalt layers crack up quicker because of an absence of a solid foundation. 
• Spiderweb or alligator cracks in a driveway could come from low-quality asphalt or concrete mix used in the making. 
• If your driveway is cracking within a few years of installation, chances are that the installation wasn’t done correctly. For instance, too much water in the concrete mix can cause early cracks. 

Why is It Important to Deal With Cracks Quickly?

You must deal with driveway cracks quickly because they can get bigger, deeper, and more problematic if ignored. 

The first thing that makes its way and invades a crack in your driveway is water. And when it does, it finds a resting spot. This is more dangerous in climates where freeze, thaw, and refreeze cycles are a common occurrence. The water expands under the surface of the driveway and crumbles the crack further. 

If your driveway has small, hairline cracks and you don’t fix them, they will eventually open enough for dirt and dust to get in. Soon after this happens, you will get to see vegetation and insects sprouting up. Small plants and grasses can damage your concrete driveway just like larger trees because they develop roots quicker. 

This can go on and your driveway cracks will keep getting bigger or protrude to a point where they become a tripping hazard.

Moreover, cracks can alter the contour of your driveway which means water may start flowing back toward the foundation of your home. A water buildup known as hydrostatic pressure can cause the foundation walls to bow. Once this happens, a plethora of related issues can occur, such as mold, cracks, chipped paint, etc.

Fixing Cracks in a Driveway – A Step-by-Step Guide

While it might seem a bit challenging to combat crack formation in driveways, you can still take timely action and stop the cracks in their tracks. Here’s how you do it:

Tools and Materials 

Here’s a list of all the tools and supplies you will need for the project:

Tools:

• Caulk gun
• Wire brush
• Paintbrush 
• Utility knife
• Broom or leaf blower
• Bucket
• Pressure washer
• Backer rod
• Tape measure
• Trowel 
• Protective clothing
• Squeegee 
• Driveway patch

Supplies:

• Water-based acrylic sealant or caulking for outdoors
• Patching compound
• Sand 

Step 1: Inspect 

Take a close look and inspect your driveway for the extent of damage and see what materials you will need. Measure all the cracks wider than a hairline with a tape measure or ruler to determine the number of supplies needed to fill them. 

Step 2: Clean and Prep

If the driveway has weeds or grass grown in the cracks, use a weed-removing tool, spade, or lawn edger to scrape it away. Use a mason chisel or hammer to chip away any crumbled or soft concrete around the cracks. 

Next, clean the driveway of all the dirt and debris. Use a stiff wire brush to effectively dislodge all the loose concrete particles and remove them from the surface. Then, use a power washer, garden hose, or air compressor for quick and thorough cleaning.

You can rent a pressure washer for about $37 per day or purchase one if you’re a regular DIYer. Pressure washers cost around $246 on average. 

Hose the driveway from the center toward the edges. Sprinkle the wet driveway with detergent and use a brush to scrub the surface clean. Hose off the soapy water and let it dry. 

If your driveway has moldy or stained areas, clean it using a mixture of ¼ cup bleach and 16 cups of water. 

Fill with Sealant 

Once your driveway is completely dry, it’s time to fill in those cracks. Driveways are typically made of two materials, concrete and asphalt. Each requires different treatment. 

Concrete

For Small (¼-inch wide) Cracks: For smaller cracks use a concrete filler or masonry crack elastomeric filler with a caulking gun. You can also add a layer of primer or a concrete bonding adhesive on the crack to create a bond between the driveway surface and the patching material. 

Choose a product with a flexible formulation so that it won’t pull away from the old concrete when it freezes and thaws. Work it into the crack with the help of a pointing trowel, push the compound in, and completely fill or “stuff” the crack. 

You can also use a cement mixture to patch thin cracks. Mix one part cement with three parts sand and work it into a stiff paste with water. In another bucket or container, mix a small amount of cement with enough water to make cement paint. 

If you can reach the inner side of the crack, start there and apply the thinner cement mixture as a primer. Let it sit for an hour then apply the cement and sand paste in a circular motion with a trowel or float. Blend and even it with the surrounding surface.

NOTE: Do not use caulk or crack fillers for hairline cracks because caulk tends to peel off the surface over time. 

For Medium (¼ to ½ inch) Cracks: Use a vinyl concrete patching compound or pre-mixed mortar. Prepare the patching compound or pre-mixed mortar as instructed by the manufacturer and pour it into the clean cracks.

Smooth it with a putty knife, press lightly, and add more until the crack is filled. 

For Large (more than ½ inch) Cracks: Cracks that are more than ⅛” wide and ½” deep are considered large cracks. Use a concrete backer rod to support them and pre-mixed concrete to patch them. The flexible backer rod is pushed into the crack to reduce the amount of filler needed. It also prevents the surface from sinking back into the crack as it dries and ages. 

Force the flexible rod into the crack with a putty knife and patch the area above it as you would with a small crack. 

Smooth the surface of the patch by feathering the compound with the trowel. Let it set for a few hours, and then cover it with a plastic sheet to keep it slightly moist for a few days. This helps the concrete to set better and longer. Follow the manufacturer’s instructions to let the compound cure. 

Then, paint or seal the surface of the repair patch and the surrounding area if needed. 

Asphalt

For Small (less than ½ inch) Cracks: Use a patching product that has some self-leveling qualities, meaning that it is liquidy. You can use a bottle of crack filler and pour it into the cracks with the help of pourable squeeze bottles. Allow this filler to set and dry for the next four to eight hours before you seal it. 

For Large (bigger than ½ inches) Cracks: Larger holes and cracks in the driveway usually have a definitive boundary. Use a water-based acrylic filler or sealer and a non-porous foam backer rod to fill the crack.

Place the backer rod inside the crack and fill it with sealant. Smooth the excess material away with a putty knife. Once you fill the cracks, wait for at least a day for the patch to cure. Then, it’s time to seal the asphalt in. Mix the sealant well in a bucket before you start. Mist the driveway with water evenly and pour a 1’ wide ribbon of sealant on the surface of the driveway. 

Use the squeegee side of a brush applicator to push, pull, and spread the sealant. Repeat the process and cover the entire area of the driveway. You can also use a paint roller to even out the sealant. 

Apply two thin coats instead of one thick coat for good results. Make sure you allow the first coat to sit and dry for four to twelve hours before applying the second one. 

Seal and Resurface

After the repair work is complete for all the cracks in your driveway, it’s time to make it all look pretty again. This means applying a sealant and then resurfacing. 

For concrete driveways, mix the resurfacing concrete into a thin pancake-batter consistency, much thinner than the one used to fill cracks. Blow off any leaves or debris, and wet the surface before applying the resurfacer. Pour a thin coat of the resurfacer when the driveway is ready and spread it with the help of a rubber squeegee. Work in small areas to avoid getting lap marks. 

You can also use a broom with an extended handle to give your concrete surface some texture. Texture prevents the driveway from becoming slippery. 

Let it Dry

Allow at least six hours before you walk on the driveway and more than 24 hours before driving on it. To be safe, we recommend leaving your driveway as is for 48 hours for everything to settle properly.

Frequently Asked Questions

Final Word

It isn’t unusual to find cracks in your driveway. An average asphalt driveway lasts for 20 to 25 years, whereas a concrete driveway may be good for more than 30 years. You can even extend the life of your driveway by fixing minor cracks when you see them with the help of this guide. If you can’t make the time or don’t feel like getting your hands dirty, you can always call a home improvement pro for the job.  

Main Image Credit: Famartin / Wikimedia Commons / CC BY-SA 4.0