Proper Depth of Fireplace
Q: What should be the interior depth of a fireplace from the back wall?
A: There is no set depth. Of course a zero clearance fireplace has a built in box that comes from the factory. Ours is 16 inches deep, which is probably quite common.
With a custom masonry fireplace, any depth is okay as long as the smoke can be directed and angled properly for the smoke to exit up through the damper. For this reason I wouldn't recommend a depth that is too shallow.
To locate a professional mason to design or build you a custom masonry fireplace, visit Home Advisor, fill out the service request and be matched with the ideal service professional in your area.
This information by Bert Roberts of General Contractor in Roseville, CA.
-- Tips courtesy of HomeAdvisor.com