Why Concrete Cracks

Why Concrete Cracks: And What You Can Do to Stop It

Customers often wonder what causes concrete to crack. Maybe you recently got concrete poured for a patio, walkway, or driveway and already notice cracking… You may wonder if your concrete contractor did a poor job either in the product they used or in the work they performed. 

Concrete is known for being one of the strongest, most durable products you can use for home improvement projects. Durable crack-resistant concrete does not happen by accident however. The process of mixing concrete, pouring concrete, and curing concrete are all highly sensitive. Thus, if the well-established guidelines are not followed perfectly, then cracking can result. 

As a homeowner, you deserve to know if you’ve gotten substandard workmanship. There are several reasons for concrete cracks, which we will outline below. 


Reason #1: Excess water in the mix

The number one reason concrete cracks we’ve seen in our thirty years in business is using excess water in the concrete mix… Concrete does not require very much water to achieve maximum strength, however, typical residential concrete contractors will pour too much water into the mix. While water makes concrete easier to set, this excess water weakens the final product.

Especially, if you live in a hot climate, shrinkage occurs when the excess water evaporates… The wetter or soupier the concrete mix, the greater the shrinkage will be. Be sure you hire a concrete contractor that can handle the job and knows how to properly mix concrete before going forward with a project. 

Reason #2: Concrete drying too fast

If concrete dries too quickly, the possibility of cracking significantly increases. The transition from concrete going from a liquid to a solid state requires enough water for the chemical reaction to work. If the concrete is dehydrated as it cures for the following days or weeks, you risk the concrete drying too quickly. When it dries too quickly, the concrete tends to crack. 

Reason #3:Using weak concrete mixes

Concrete strength is measured in pounds per square inch (PSI). The higher the PSI the more durable your concrete will be and will thus be resilient to cracking. The average residential project uses a minimum of 2,500 to 3,000 PSI; however if you’re concerned about cracking then we recommend talking to your concrete contractor about stronger products on the market.

Reason #4: Lack of contraction/control joints

In a concrete slab, control joints help control cracking on the surface. The joints should be of the depth of the slab and no more than 2-3 times (in feet) of the thickness of the concrete (in inches).This will help reduce random cracking on the surface and will help your patio, walkway, or driveway look great year-round.

Reason #5: Foundations poured in the winter

Concrete poured in the cold, winter months will be prone to cracking when left unheated. When the water in the cement mix freezes, cracking is the result.  If the foundations are improperly compacted, the concrete will inevitably develop more cracks as well. 

Sam the Concrete Man: Partnering With Concrete Experts

In an ideal world, there would be no cracking in concrete. However, minor cracking should be expected especially for large projects, but there are many things you can do to reduce the risk of any unsightly cracks on your walkway, patio, or driveway. By following these tips you’ll be sure to keep your concrete looking pristine for years to come. 

One thing all concrete professionals know and should tell their customers is that cracking is not uncommon and often inevitable – regardless of the skill of the installing team. According to the American Concrete Institute “Even with the best floor designs and proper construction, it is unrealistic to expect crack-free and curl-free floors.

If you have any doubt about doing it yourself, be sure to get a free estimate from our experienced contractors. Our concrete contractors are well versed in pouring concrete resilient to cracking, given our adherence to quality products and quality workmanship 


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