If you are wondering why anyone would want a cricket, as in a little insect, behind the chimney then you have never learned, or heard, that third meaning of the word cricket.

A cricket, also called a saddle flashing, is a device that should be put behind a wide chimney. You can see that, while not perfect perhaps, it does help guide leaves, debris and water around the chimney instead of it all collecting across the chimney in back. At the above chimney that moisture had lead to damage of the roof sheathing at that location. That much was clear, despite limited visibility. Recommended widths vary -- that is when is the cricket needed, depending on whom you talk to, but certainly this chimney needs one. A photo of a cricket is below. 

Some people believe a cricket should be installed on any chimney that is two feet or more across. Others go with 30 inches and wider.

Steven L. Smith

Bellingham WA Home Inspections