How tall should a fireplace mantel be?
Consequently, how high should your fireplace mantel be?
about 12 inches
Similarly, how high should fireplace be off floor? 40"-42"
Also, how far should a mantel stick out?
If the mantel will stick out from the wall more than 1 1/2 inches, the height between the top of the fireplace and the shelf must be 12 inches or more. Always check with your local planning and building office for code requirements.
How wide should the fireplace mantel be?
For a quick reference, a 36-inch fireplace will probably have a mantel width of 48 inches. A 42-inch fireplace will probably have a mantel width of 54 inches. The mantel should not be so wide that it reaches anything else, like a wall, window or door.