I have a small gas fireplace already installed. I cut a hole in side and it looks like it has about a foot clearance (opening between the outer wall and fireplace housing). In addition, it looks like there is 16 inches above the top for the fireplace and the bottom of the mantle.
I would like to reduce the clearance to 14 or 12 inches and wanted to know what is the correct clearance. Additionally, I wanted to check if any mantel shield would be recommended as I would like to put a wood mantle on top.