According to the National Association of Certified Home Inspectors (NACHI), a chimney cricket is a small peaked roof which is installed on the back side of your chimney to deflect water and debris from your chimney.
This business had issues with water backing up at the fireplace and leaking in behind the chimney. By installing the chimney cricket, water is diverted so that it no longer pools and causes problems.
See images below for basic layers and installation
A frame is built on the back side of the chimney. The height depends on the roof slope. 
Sheathing is added on top of the frame to support the next roofing shingles 
Protective underlayment is added, then metal flashing and finally shingles.
For roofing installations and repairs in the Greater Nashville Area, call us for an onsite estimate 615-784-4628
