Fireplace Installed Flush On The Floor And Hearth Extension Raised To Bottom Of Firebox Opening - Heatilator BIR42-B Installation Manual

1. Fireplace Installed Flush on the Floor and
Hearth Extension Raised to Bottom of Firebox
Opening
Non-combustible flooring a minimum of 20 in. (508
mm) in front of and 12 in. (305 mm) to each side of the
fuel opening is required.
The hearth framing must be constructed of non-com-
bustible materials (such as metal framing or equivalent
material) and placed on HX3(s) or HX4(s) and 1/2 in.
Durock, or equivalent material. Refer to Figure 7.5.
When creating the platform, allow for the thickness
of the non-combustible finishing materials.
Seal gaps between the hearth extension and the front
of the fireplace with a bead of non-combustible sealant
or grout.
Note: The bottom of the fireplace opening is 3-3/4 in. (95.3mm) above
the bottom of the fireplace. Finished hearth must NOT extend above this
level.
Continuous,
non-combustible sealant
Durock Tile, stone or other
non-combustible material
1 in. Micore and 1/2
in. Durock or
equivalent insulation
(see Table)
Floor constructed of wood or
other combustible material
Figure 7.5 Hearth Extension Construction
30 Heatilator • Birmingham 42-B Installation Manual • 4059-715 • Rev P • 09/28/15
Protective
Metal Hearth
Strip
*
*
* 2 in. (51 mm)
Note: The bottom of the fireplace
opening is 3-3/4 in. (95.3 mm)
above the bottom of the
fireplace. Finished hearth must
NOT extend above this level.
Noncombustible
Finishing Material
Hearth Extension
Noncombustible
Framing Material
1 in. Micore and
1/2 in. Durock
or equivalent
insulation
Figure 7.6 Raised Platform Hearth Extension Detail
Noncombustible
Framing Material
Figure 7.7 Raised Platform Hearth Extension-Framing
Non-combustible
Finishing Materials
Figure 7.8 Raised Platform Hearth Extension-Finishing
20 in. Min.
Protective Metal
Hearth Strips
HX4 or
equivalent
Floor