Heatilator BIR42 Owner's Manual page 42

IMPORTANT!
Continuous,
non-combustible sealant
Durock Tile, stone or other
non-combustible material
1 in. Micore or
equivalent insulation
(see Table)
Floor constructed of wood or
other combustible material
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.
20 in. Min.
Hearth Extension
Non-combustible
Finishing Material
1 in. Micore or
equivalent insulation
& 1/2 in. Durock
Protective
Metal Hearth
Strip
*
*
* 2 in. (51 mm)
Bottom of
fireplace opening
Platform must be built
to raise the bottom of
the fireplace opening
to the level of the
desired hearth height.
Protective Metal
Hearth Strips Floor
Non-combustible
Framing Material
Non-combustible
Framing Material
Non-combustible
Finishing Materials
1 in. Micore or
equivalent insulation
& 1/2 in. Durock