Shrinkage Cracks—Why They Happen and How We Control Them

Hairline cracks are thin, surface-level cracks that form as concrete cures and dries. During the curing process, the concrete naturally shrinks as water evaporates, which can cause small cracks to appear. These cracks are common and expected in new concrete but don’t affect its structural integrity.

While they are normal, homeowners are often concerned when these hairline cracks appear within the first few weeks or months. It’s important to remember that these cracks are surface-level and not a sign of a defective installation. However, we understand that they can be a cosmetic issue, which is why we take proactive steps to minimize their occurrence.

One of the most effective ways to manage hairline cracks is through the use of control joints. These are intentional cuts made in the concrete to direct where cracks are most likely to form. Since shrinkage cracking is inevitable, control joints provide a controlled area where cracks are more likely to occur, keeping them from forming randomly across the surface.

At Richfield Concrete, we go beyond industry standards by placing control joints no more than 8 feet apart. This reduces the likelihood of cracks occurring in places that are less visible or noticeable. Control joints help guide the cracks in predictable locations, improving the overall aesthetic and durability of the concrete.

While we can’t guarantee that all cracks will occur exactly at the joint, properly placed control joints greatly increase the chances that the cracks will follow a designated path.

Another factor in minimizing hairline cracks is the use of proper curing methods. That’s why we incorporate the E5 Internal Cure admixture in our concrete mix. Unlike traditional curing methods that rely on surface treatments, E5 works from the inside out by improving moisture retention within the slab, leading to more uniform curing and less cracking over time.

The National Ready Mixed Concrete Association (NRMCA) notes that internal curing technologies like E5 can help reduce shrinkage cracking by maintaining consistent moisture levels during the curing process. By controlling hydration from within, we help ensure the concrete cures evenly, reducing internal stress and the potential for cracking.

Another advantage of using E5 is that it allows us to use a much lower water-to-cement ratio than industry standards, without compromising workability. Lowering the water content in concrete helps reduce the shrinkage that can lead to cracks. The E5 admixture makes it possible to achieve a balanced mix that reduces cracking while maintaining the ease of finishing and durability.

What Homeowners Can Expect

Even with the best techniques in place, it’s important to set realistic expectations. Hairline cracks may still appear, but these are typically cosmetic and don’t affect the performance of your concrete. If a crack widens or becomes more noticeable, homeowners can fill it with a polyurethane crack filler to prevent moisture infiltration, but in most cases, these small cracks won’t cause long-term problems.

At Richfield Concrete, we take extra steps to ensure your concrete surfaces are durable, functional, and aesthetically pleasing. By using control joints no more than 8 feet apart, the E5 Internal Cure admixture, and a lower water-to-cement ratio, we help reduce the occurrence of hairline cracks and enhance the long-term performance of your concrete.

While hairline cracks are natural and common, we focus on using the best practices to minimize them and maintain the beauty and strength of your concrete. Thanks for listening to Episode 2 of the Richfield Concrete Podcast! If you have any questions about your concrete or would like to schedule an estimate, don’t hesitate to reach out.

Contact Us

Have more questions? Reach out to us today to learn how Richfield Concrete can help with your concrete needs. Whether it’s a new installation or you need advice on managing cracks, we’re here to assist you!