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FIREPLACE INSTALLATION
STEP 3: FIREBOX ASSEMBLY
BASE PLATE
A two-part base plate is included with this fireplace kit.
The base plate must be placed on a level noncombustible
surface. It is very important that your base plate be square
to the room, properly centered, and level. Mark out the
position of the base plate on the supporting floor system.
Apply a layer of mortar to the area and set the base plate
pieces, mortaring the two pieces together using FireRock
Adhesive Mortar (Figure 6.1).
Whether using a flush hearth or a raised hearth, a
noncombustible hearth must extend at least 32” out in
front of the finished firebox opening and 8” beyond the
finished sides of the opening (Figure 2.1 on page 18).
FLUSH HEARTH (FIGURE 6.2)
If the design calls for a flush hearth, you can omit the base
plate from the assembly instructions and build the side
walls directly on the concrete pad or slab. In the event you
opt not to use the base plate, carefully chalk lines where the
base plate would be to ensure proper placement of your
firebox.
With a flush hearth, the firebrick floor of the firebox will be
applied directly to the concrete slab or pad. This makes the
finished firebrick floor approximately 2 1/2” above the top of
the slab or pad.
RAISED HEARTH (FIGURE 6.3)
If the design calls for a raised hearth, the base plate should
be set on a noncombustible platform that is built up to the
desired hearth height.
When calculating the hearth height, be sure to account for
both the 3 3/4” base plate and 2 1/2” thick firebrick floor, in
addition to the height of the platform.
FIGURE 6.2
FLUSH HEARTH
FIGURE 6.3
RAISED HEARTH
FIGURE 6.1
2 PIECE BASE PLATE ON CONCRETE SLAB
