How To Prevent Driveway Cracks?

As driveways age, cracks are inevitable. But a well built driveway should last for well over 10 years before you start to see any major cracks. 

If cracks develop a few months or a couple years after the driveway was laid, there is a problem with the driveway. 

In this guide, we discuss what causes cracks on driveways, how to prevent driveway cracks, and what you can do when cracks appear on your driveway. 

Why Driveways Crack?

Why Driveways Crack? 

No matter how well you take care of your driveway, cracks are virtually inevitable. Asphalt and concrete driveways don’t last forever. 

After several years, you’ll start to notice small cracks in various places on the driveway. By the time the driveway is getting to the end of its 20-30 year lifespan, it will probably have big cracks all over. 

But driveways can also crack prematurely because of a number of factors, most of them having to do with how the driveway was laid. 

Here are the most common reasons why driveways crack, other than normal aging. 

  • Poor foundation. The quality and strength of the base layer of a driveway matter a great deal. Using the wrong base materials, making the base too thin and not compacting the materials can all lead to a weak base that causes the driveway surface to crack. 
  • Too much water in the concrete mix. You (or the contractors) may be tempted to add more water to a concrete mix to make it easier to pour. But a too wet concrete mix is more likely to crack. As water leaves the concrete, it shrinks more than it should, leading to cracks. 
  • Concrete drying too quickly. For a concrete driveway to properly set and cure, it needs to dry slowly and evenly. This is why it’s important to water the surface of the driveway during the curing period, which is usually 28 days long. It prevents the surface from getting too dry and cracking. Alternatively, apply a curing compound. 
  • Poor drainage. Standing water on the driveway could weaken it and lead to cracking. This happens when water seeps inside the porous asphalt or concrete, then contracts and expands with temperature changes. This eventually causes cracks on the driveway.
  • Water flowing uncontrollably across or along the driveway can also damage it. It gradually washes away material from the base, which reduces support to the driveway. Eventually, the driveway begins to sink and crack. 
  • Overloading the driveway is another common cause of cracks. Each driveway has a load bearing limit depending on the thickness of the base and the materials used to lay the driveway (e.g. the type of concrete mix). If you overload the driveway with heavy vehicles or machinery, it’ll crack. 
  • Tree roots growing under the driveway can lift the surface and break it apart. 
  • Extreme weather. Even if you take care to lay the driveway properly, extreme weather can still create cracks on it. Heat waves can stress both concrete and asphalt to the point of crackign or buckling. Extreme cold can also cause the driveway and the earth underneath to contract or expand (because of frost), leading to cracks. 

How To Prevent Driveway Cracks 

Here are the best ways to prevent driveway cracks. 

1. Build A Strong Base 

The base layer provides most of the support on a driveway. Whether you are laying a paver, gravel, asphalt or concrete driveway, the first step is to build a proper base. 

Once you excavate the ground, the first step is to compact the soil to support the weight of the base layer. 

Then you lay the base materials in layers. Typically, crushed gravel, limestone or granite is used in the base. 

Lay two inches of base material at a time then compact it before laying more material. The overall thickness of the base should be between 4 and 8 inches depending on the type of soil in your area and how strong you want the driveway to be. 

A layer of sand is usually poured over the base to provide drainage. 

Tip: If you are building a concrete driveway, saturate the base with water just before you pour concrete. This prevents the dry base from sucking moisture from the concrete and drying it out too quickly. 

2. Avoid Too Much Water In The Concrete Mix

Use the recommended water to cement ratio when preparing the concrete mix for a driveway. The exact ratio depends on the type of cement you are using but it generally ranges between 0.40 and 0.60. 

That means using 40-60 pounds of water for every 100 pounds of cement. Any more water than that results in a concrete mix that’s too porous and vulnerable to cracking. 

If the concrete mix is difficult to work with, you should add plasticizer instead of water to improve its workability.

3. Proper Curing 

After the concrete driveway is finished, you don’t want it to dry too fast. That keeps it from achieving its full strength, leaving it at risk of cracking. 

You also don’t want it to dry unevenly, which happens when wind and sun dries out concrete that’s on the surface faster than the one that is deeper. 

The best way to cure a concrete driveway is moist curing. You water the concrete 5 to 7 times a day for the first seven days. 

This keeps the surface of the driveway moist, giving the concrete time to cure and harden.    

If moist curing is not possible, you can apply a curing compound on the concrete driveway as soon as it’s finished. 

The compound forms a film on the surface of the concrete to prevent evaporation. This keeps the concrete moist throughout the curing process. 

4. Pay Attention to Drainage When Laying The Driveway 

Proper drainage should be included in a driveway’s design and construction. Don’t do it as an afterthought once the driveway is already laid. 

There are two driveway drainage issues you should avoid: standing water and flowing water that erodes the driveway. 

Things like crowning the driveway, building the driveway with a slight grade, and installing drainage ditches on the side, and building drainage channels can help prevent these problems. 

In some cases, you have to tackle poor drainage before it reaches the driveway. Building a French drain or a swale can help capture and redirect heavy runoff before it reaches the driveway.    

5. Sealcoat The Driveway 

Sealcoating your driveway is one of the best things you can do to increase its longevity and prevent cracks. 

The sealant protects the driveway from moisture damage, extreme weather, erosion and other problems. 

There are different kinds of sealants including asphalt emulsion, acrylic, polyurethane and epoxy. 

Note: Wait at least 28 days before sealing a new concrete driveway and 6-12 months for an asphalt driveway. This ensures the driveway has completely cured before you apply sealant on it. 

6. Add Control Joints To A Concrete Driveway

One way to keep a concrete driveway from cracking is to control where it cracks by adding control expansion joints. 

These are lines cut into the concrete to a quarter of its depth.  The lines provide a place for the concrete to expand and contract. 

When the concrete expands or contracts – because of weather changes or earth movements – it will crack in a controlled way along these joints rather than leaving unsightly cracks all over. 

Here’s a video explaining more on concrete control joints. 

Cut joints into the concrete driveway 6-18 hours after it’s poured. The joints should be spaced 2-3 times (in feet) the slab thickness (in inches). 

So if you have a 3” thick concrete slab on your driveway, the control joints should be 6 to 9 feet apart.   

7. Fix Small Cracks Immediately

It is normal for small cracks to appear on a relatively new driveway. Even if you did everything right, factors beyond your control such as weather can still cause cracks. 

Don’t ignore these cracks as they can grow wider and more difficult to fix. 

As water settles in the cracks, it will freeze and thaw as temperatures change. This frequent expansion and contraction causes the cracks to widen. 

Weeds and grass can also start growing in the cracks, causing them to widen. You may also notice ants starting to come through the cracks from their underground nests. As they excavate tunnels, they weaken the base layer, further damaging the driveway. 

There are plenty of sealants and fillers that can fix small cracks. Make sure you pick the right one for your type of driveway. 

Do Paver Driveways Crack?

We’ve mostly focused on asphalt and concrete driveways in this guide. That’s because these are the types of driveways most vulnerable to cracks. 

What about paver driveways? Do you need to worry about them cracking?

Usually, driveway pavers don’t crack because they are individual units. Instead, they sink or shift. The most common cause of this is a poorly laid base layer.   

That’s not to mean that driveway pavers never crack. Luckily, that’s easy to fix. You just replace the cracked paver. 

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