Travis Industries Revolution 36CF Installation Manual page 32

A hearth is not required if the fireplace is raised 6" above the
flooring surface. NOTE: Make sure to accommodate the flooring
surface - this distance must be measured from the top of carpeting
or other flooring material.
WARNING:
We recommend a hearth to protect the flooring
surface from discoloration or other negative
impact from the heater, especially if it is near the
minimum raised height.
Side View
1"
NOTE: When building a raised fireplace, consider the facing
material below the fireplace. If using tile, you may wish to
make the platform a suitable height for un-cut tile. For
example, if using 12" tile, make the platform 11" tall (10-1/2"
section of framing + 1/2" plywood).