Control joints control cracking - most of the time

Cracks in concrete are a sore subject for any concrete contractor. No one likes to see in cracks in their concrete. Sometimes customers want a guarantee that their concrete won't crack.  So what can we do about it?

First of all there is a good chance that your concrete will crack. With the settling and movement of the earth and the freezing & thawing here in Ohio, there is a much better chance of cracking than not. We would be more likely to guarantee that you will get a crack than not. Does that make us a bad concrete contractor and that we don't know what we are doing? Absolutely not. Please keep reading.

Cracks followed he tooled control joints

The first thing a good contractor like Yoder Concrete Construction, LLC will do is to make sure the concrete is placed on a mechanically compacted based. We typically use a gravel or limestone mixed with dust that compacts very well.

The next thing to do is not preventing cracks, but controlling them with control joints.

Control joints are strategically placed cuts, expansion strips or lines tooled into the concrete with the intent that any cracking that might occur in the slab will follow these weakened joints. They are placed at predetermined locations based upon the thickness and width of the slab or often at corner or posts. In the picture above, you might be able to see that a crack followed the joint that the contractor placed in the concrete sidewalk. The crack is hidden in the joint and not greatly visible to the eye. In the absence of the control joint, the crack would have been very random and visibly distracting.

Does the crack always follow the control joint?  Unfortunately no. See the picture above. I had to take this picture. I was amazed. There are three control joints at the corner of this sidewalk, and the crack chose to randomly take its own path. Was this the fault of the contractor? Not at all. Cracks will do their own thing. We can only do our best to control them.

Occasionally we will have a customer that does not want control joints in their concrete. That is an acceptable decision, but they need to remember that there is always a chance of cracking, and it will occur randomly. The sidewalk shown above is stamped in a random stone pattern with a solid border. Because of the random pattern, the customer chose not to put a straight line in the walk. A control joint would not have prevented the crack, but would have hidden the crack in a straight line. 

I hope this post clarifies concrete cracking and what we do about it. Do you still have questions? Please let me know. I'd love to hear your opinion on this!