Why California patches fail: more on patching rated walls (part 2) 

Thanks for the great response on the last post related to patching rated walls. I have more to share in the future, but I need time to create the content. Many of you liked the post, so I’m sharing additional information that I’ve already prepared to help you advance further.

Three key reasons why California patches fail in fire tests:

  1. It will fail at the hose stream test. For more information on this, check out this series we did a while back on Hose Stream and imagine that patch, or any patch you accept being able to pass the hose stream test as it is described in these posts from 2016.
  1. You will fail to achieve the T rating, which all rated walls and floors must meet. There is a bit of information in this article here
  1. As the drywall patch (or GOD FORBID drywall tape and mud excuse for a patch) heats up in a fire it will shrink. As the existing wall dries up it shrinks as well. When this happens the gap between the existing wall and the patch material grows. This makes it easier for the patch to dislodge during the hose stream test and this gap will allow hot gasses through and that is how the T rating segment of the test will fail. 

So, the next time you see a patch in a rated wall, think about why California patches fail. Verify the patch to make sure it won’t introduce any risks for your project or the people who will live, work, and play in the building later on.

As always, thanks for taking the time to learn more about the industry I love. If we can help you on any project you are working on, don’t hesitate to reach out to us