13
For a raised hearth (floor of the firebox elevated
above the room’s floor) then the Vent-Free base plate
can be set on a concrete block platform that is built up to
the desired raised hearth height on the concrete support
slab.
(Figure 12)
When calculating raised hearth height, be sure to
allow for the three inch (3”) thick base plate plus the one
and one-half inch (1-1/2”) thick fire brick floor in addition
to the height of the concrete block platform. CMU used
for base plate support should be rated ASTM 90.
For a “flush hearth” (firebox floor flush with the
room’s floor) the base plate can be omitted from the
assembly and the firebox walls built directly on the
concrete support slab as long as there are no wood
underpinnings. This makes the firebox finished fire
brick floor approximately one and one-half inches (1-
1/2”) above the top of the concrete support slab. For
installation directly on a combustible floor, the base plate
must be used.
(Figure 13)
Earthcore Industries
12/2016
Vent-Free Gas Firebox
Raised and Flush Hearth Application
Standard Residential
Concrete Slab
On or Off-Grade
Base Plate
Raised Platform
FIGURE 12
FIGURE 13
