Why Does Concrete Crack?

Concrete is a durable, hardy material—so why did your brand-new concrete just crack? In addition to being unsightly and potentially dangerous, cracked concrete presents major issues for foundations and other structural supports. Generally, concrete cracks when it shrinks, which could happen for a number of reasons—but experienced contractors know that concrete shrinks about an eighth of an inch every 20 feet, and will make adjustments to ensure a crack-free structure.
Read on to learn more about what causes concrete to crack and how to prevent it. When you’re choosing a concrete foundation contractor in Western NY, ask them how they prevent cracking problems and what to do if your new concrete cracks:

  • Too much water: When there’s too much water in the concrete mix, it will shrink too much—the volume of the mix is thrown off, so what would ordinarily be the right amount of properly-mixed concrete will shrink and crack into a smaller volume as the water evaporates and it hardens. This can be avoided by following the concrete mixing instructions to the letter.
  • Improper curing: When water evaporates from concrete too quickly, the surface will crack while the concrete underneath is still wet. This is called map cracking, and it happens when the concrete doesn’t cure properly. Usually this is just cosmetic damage, but in some cases, it can be quite severe. Major cracks will need to be repaired, and in worst-case scenarios, the concrete may need to be re-poured. Contractors monitor curing by applying a curing compound, then monitoring it closely for about a week. This keeps the concrete evenly moist as it dries and cures, resulting in a crack-free base.
  • Poor sub base preparation: You need a good sub base in order to get great results from your concrete. If the base is uneven, frozen or has poor drainage, the ground—and your concrete—will shift and crack. Make sure your concrete contractor in Western NY understands the importance of a good sub base.
  • Lack of contraction joints: When working with concrete, most contractors understand that shrinkage will happen. Contraction joints are used to give the concrete a designated place to contract without cracking, much like the panels in a sidewalk. These joints are formed using wood or plastic, and are best created in square patterns. If your concrete doesn’t include contraction joints, it will be more prone to cracking on its own.
  • Improperly sealed joints: Sealing your joints makes it harder for water and other materials to get into the joints, which is what eventually causes problems as the concrete expands and contracts with the weather. The sealant you use needs to be waterproof and able to expand and contract along with the concrete—otherwise it won’t function properly, and may lead to issues later on down the line.

For affordable and reliable concrete contractors in Western NY, look no further than Bri-Mic Construction, Inc. Call us today to get started on your next concrete project—whether you’re interested in a foundation pour or are looking to build a patio or retaining wall, we’d be glad to help!