Beneath Hearth Extension; Hearth Extension; Mantel - RSF Woodburning Fireplaces ONYX AP Owner's Manual

BENEATH HEARTH EXTENSION

Unless raised 4" above the base of the
hearth, the Onyx AP must use a 1/2" Durock
ciment board with a metal sheet (0.025") or a
3/4" Micore 160 board beneath the hearth
extension (non-combustible material).
If the fireplace is raised 4" or more, the area
in front of the fireplace just needs to be
covered with a non-combustible material,
such as metal, brick, stone or slate. There is
no minimum thickness required for this non-
combustible hearth extension. The 5" wide
spark guard must be installed underneath
either the hearth extension or the protective
board.
NOTE: If the Onyx AP is installed on a con-
crete floor, the protective board and spark
guards are not required.

HEARTH EXTENSION

The area immediately in front of the fireplace
must be protected by a non-combustible
material such as brick, tile, stone, or slate.
The protection must extend at least 16" in front (See figure
14) of the fireplace door opening. There is no minimum thick-
ness required for the hearth extension.

MANTEL

A masonry or other non-combustible mantel may be placed
directly above the top louvers. If a wood or other combustible
mantel is desired, it must be at least 14 inches above the top
of door (See Figure 14 & 15).
ONYX AP Owner's Manual
5" max out from face
6 1/4" min. to com-
bustible surround
8 1/2" min. to side wall
42"
Protective board
1/2" Durock with
metal sheet or 3/4"
Micore board
Non-combustible material
(permanently attached)
Figure 14: Clearances to combustibles and hearth requirements
12"
max.
Sheeting
Silicone
seal
Sheeting
Silicone
seal
Non-
combustible
material
Figure 15 : Mantel installation
16
14" min. from top of door (40" min.
from the base of the fireplace)
28"
20 min"
Non-combustible
material
RAISED INSTALLATION
16"
42"
z-shaped spark guard
5 1/2"
max.
No combustible materials
behind sheeting below
this line
12" max.
Silicone
seal
Expanded metal
Metal
14" min. Facing
2" min.
Header
Adjustment slot
With FDKO facing kit
RSF Woodburning Fireplaces
0" clearance to
stand off
39"
23"
5" wide spark
guard
4"
Header