A chimney cricket is one of the funnier-sounding parts of your chimney. As fun as this would be, it definitely does not have anything to do with a little chirping insect reminiscent of summer nights or a little cartoon character that might come to mind. So, what exactly is a chimney cricket?
A chimney cricket is a roofing component required by IRC code 903.2.2 for all chimneys over 30 inches (you can often estimate this to be anything over four bricks). This is essentially just an extension of your roof that runs perpendicular to your main roof between your chimney and the main roof. It covers the width of your chimney and usually follows the same pitch as the rest of your roof. Ok, so now that we have a working definition of what exactly a cricket is, let’s explain the most important question: why you need one. As water flows down your roof, it essentially acts like a waterfall, and gravity gives it more and more speed as it goes down your roof. Often, the force of this water can overwhelm the normal flashing around your chimney and lead to leaks.
Further, wide chimneys can trap leaf matter and water behind the chimney and lead to rusting of the flashing. With a cricket installed, however, water flows down the roof, over the sides of the cricket, and off the roof around the chimney, preventing possible water intrusion behind the chimney. If your chimney is over 30 inches wide, we always recommend having a chimney cricket installed.