A “cricket” is generally a piece of metal flashing next to a chimney used to divert water to the side of the chimney. In some instances the cricket may be partially framed with roofing material over sloped wood framing, including some metal flashing materials as well.
If there is no cricket:
Without a cricket water may puddle and not drain well behind the chimney, or debris may build-up. The potential for moisture intrusion increases. If the chimney is less than 30 inches wide, many professionals will not even recommend a cricket.
A cricket is a plus, but not having one does not necessarily mean that there will be a leak. The cricket just helps reduce the chances of a leak.
Adding or repairing
Roofers and qualified handymen can generally repair or add a cricket if needed. Another way of handling this, is to wait until you decide to re-roof the home, and at at that time, install a cricket.Who to consult? Roofers, fireplace contractors and qualified handymen.
When a cricket needs repairing a qualified handyman or roofer will often do this work. The most proficient at installing a new cricket is usually a fireplace specialist or roofer.