How To Fix Hairline Cracks In A Concrete Driveway

Cracks in your driveway are unsightly and can become a serious hazard over time if not properly dealt with. By examining the concrete's overall condition at least once a year, you can fix any problem areas before they have the chance to expand deeper. Having a completely crack-free driveway would be impossible, so instead, prioritize which ones need to be fixed first, then choose a method depending on the severity of the crack. We've researched how to best repair hairline cracks in concrete, so you'll know which method to choose for your driveway issues.

Extremely fine hairline cracks (less than 1/16 inch)

  • Surface cracks require surface treatments such as sealers or pouring a new thin layer of concrete on top.

Hairline cracks (less than 1/4 inch)

  • Address hairline cracks by applying a crack filler to hide the void and protect it from widening. 

Wider cracks (more than 1/4 inch)

  • Wider cracks may require more involved methods of crack filling or possible replacement, depending on the severity. 

Before you start trying to track down every single crack, it's best to familiarize yourself with the basic properties of concrete to understand the underlying issues. This will help you choose the best repair method for the cracks you are experiencing and allow for the longest-lasting fix. Read on below for more info on concrete properties and the best repair methods to fix up any cracks you may have in your driveway.

Hairline cracks on the driveway, How To Fix Hairline Cracks In A Concrete Driveway

Repair Methods for Cracked Concrete

A hairline crack on the driveway

These fixes are all easily accomplished with the right few tools and determination, so don't be afraid to tackle this simple yet rewarding job yourself. Most of the work here is in the surface prep, so depending on how large your driveway is, this could be the biggest time-consuming part of the project. Plan on keeping your car off of the driveway throughout this entire process and for some time afterward to allow the product to reach full strength before driving on it.

Extremely fine hairline cracks

Spiderwebbing or crazing is a type of cracking that can occur when the concrete cures improperly, causing a noticeable surface shrinkage. Very fine hairline cracks are usually not a serious strength issue as long as there are no other signs of deeper cracking going on in the area. Although they are very shallow in-depth, they can still be undesirable to look at every time you're in the driveway.

If your driveway suffers from crazing, then you can try one of these fixes to minimize the overall appearance and help protect from weather conditions.

Float Layer

Pouring a thin layer of concrete resurfacer will bond to the existing slab and present a fresh surface finish. To pour a float layer, first prepare the surface by removing all debris with a pressure washer to clean and rough up the surface. Patch any pits or holes with mortar and allow to dry for the smoothest final product.

Next, following the instructions, mix the appropriate amount of water in a bucket with the resurfacer and mix thoroughly. Pour directly onto the driveway and use a trowel to evenly spread the product over the entire area. Finally, apply a light brush finish to smooth out the texture and then allow it to dry fully before putting any weight on it.


Another option to minimize existing crazing is to apply a penetrating sealer to protect the surface and repel moisture. It will feather the lines together with the texture of the concrete and in a matte finish, you can hardly tell there is even anything on there. You can also consider acid staining the concrete for a different type of surface look with a darker color to help the lines appear less noticeable.

Hairline cracks

A huge and long crack on the road

Hairline cracks are less than a 1/4 inch wide and are commonly seen in driveways and sidewalks. Fixing these types of cracks is as simple as proper surface preparation and choosing an appropriate type of crack filler. Depending on your climate, this may become an annual routine, but it's well worth it for the peace of mind knowing your driveway is in its best possible condition.

Surface Preparation

Starting with a suitable surface is the first step to repairing any cracks. Identify which cracks you will be filling, then clean the channel with a wire brush to remove all loose rocks, debris, and any filler from previous applications. Wash the entire driveway using a pressure washer or a hose with a scrub brush to ensure no dust particles will prevent the filler from sticking. Let the concrete dry completely before moving to the next step of applying a filler.

Product Application

Choose a suitable type of concrete filler product for your crack. Follow the specific instructions for the product you select, but most cases will call for either using a caulk tube or mixing mortar to fill the cracks. Most caulks can be squeezed on and then shaped and smoothed to ensure the bead is covering the area. Mortars will entail mixing well with water in a bucket then using a trowel to scrape and smooth the cement mixture into the cracks. Caulk is preferred for precision and color matching, while the mortar can cover more area at once and blends in a bit more naturally.

Wider cracks 

A cracked concrete road

Cracks wider than 1/4 inch are a bit more challenging to repair but can be filled similarly to the method mentioned above. During the surface preparation stage, you might consider using a grinding wheel to intentionally widen the groove to create a more suitable channel for the mortar to fill. Crumbling areas will need to be cleaned with a hammer and chisel until all loose pieces are removed, leaving a solid surface to build on top of.

Other techniques involve reinforcing the cavity with an expansion joint to minimize the amount of filler material required. Serious repairs might involve using rebar to drill into the existing slab and tie into a new pour. Caulk is not recommended for wider fills. If it's a more serious crack, consider getting a quote on a new driveway installation.

Can you use FlexSeal to fill driveway cracks?

Flexseal is an easy-to-use rubber product available in paint, spray, or caulk form that you can apply to fill in driveway cracks in a pinch. It's self-leveling and UV resistant, making it well suited for this application but expect to reapply the product seasonally depending on your climate. Different sizes of cracks may lend themselves better to different applications, but the caulk version is ideal for most instances.

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Is cracking in concrete normal?

Part of pouring concrete is recognizing that cracks will occur, and the best strategy is to reduce or hide them as much as possible. When concrete is poured, grooves are tooled into the wet surface to create channels for future cracks to form along as stresses happen.

Larger driveways may be poured in multiple sections or require an expansion joint to be cut into the slab with a diamond saw after curing. Being that the concrete is constantly exposed to the elements, weathering will occur much like the process that occurs in nature.

What causes concrete to crack?

Cracking is caused by various environmental factors, including shifts in the ground, the freeze-thaw cycle, and stress from driving your car over it constantly. It's also possible the concrete wasn't poured with ideal curing conditions or on loosely compacted ground, causing cracks from settling. If the concrete cured too fast, then the outside layer can slightly shrink, leading to fine, crazing lines. The added stress from heavyweight loads will also cause cracking, so avoid parking too many vehicles there at a time.

Should you fix hairline cracks in concrete?

It's best to fix cracks in concrete to improve the appearance and to prevent the cracks from becoming worse over time. While not all cracks will cause structural concern, being proactive about filling them will eliminate the chance for them to widen with weather conditions. Small hairline cracks will worsen if left exposed, especially in harsh climates. The biggest concern is water can freeze and expand in the cracks as concrete already naturally absorbs water and will collect in areas where cracks are present. 

How to prevent cracking in concrete?

Cracking is a normal quality of concrete, and there are few things you can do to prevent it other than making sure the concrete was properly poured in the first place. You can perform preventative measures to mitigate weathering effects, like always applying a yearly surface sealer and filling any hairline cracks to protect them from further freeze-thaw damage.

Tree roots growing underneath your driveway are another common cause of cracking, and because removal can be harmful to the tree, it's recommended you consult a professional for advice. 

Does homeowners insurance cover a cracked driveway?

Most homeowner's policies consider an attached driveway part of the house and will likely extend the same coverage. If the cracking was caused by an accident or event that you will be filing an insurance claim for, then be sure to ask your agent about covering the driveway repair as well. This typically doesn't include cracks caused by normal concrete curing and earth shifting, but it's always worth asking about more severe cracks that could be potentially hazardous.

In Summary

While we can't always stop concrete from cracking in the first place, we can be reactive about how we choose to repair it when it does. Paying attention to the condition of cracks as they develop will ensure you can repair them and prevent them from ever becoming a bigger issue. If your concrete is severely cracked, consider tearing it out, adding curb appeal with a new driveway.

Check out our other articles on inspiring driveway ideas with pavers or gravel style entries:

21 Paver Driveway Ideas To Consider

21 Gorgeous Gravel Driveway Ideas

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