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Important: Since there is no re brick set along the top of the IBV rebox opening, when setting the noncombustible facing
material (code required and supplied by others) onto the drywall across the top of the rebox opening there will be a gap between
the back of the noncombustible nish material and the rough front face of the Isokern Smoke Dome (Figure 29).
Be sure to ll this gap with Earthcore Mortar (or similar noncombustible grout) in conjunction with placement of the code
required noncombustible nish facing material that is set across the top of the rebox opening.
WARNING: Avoid false chimneys.
Important: Failure to seal any gaps between the front face of the IBV and the back of the noncombustible nished facing
material will create what is known as a “false chimney” or “secondary chimney”. A “false chimney”, in this case is the narrow gap
(mentioned above) between the back of the noncombustible facing material at the top of the rebox opening and the rough front
of the IBV smoke dome. If left unlled this gap creates a “false chimney” which can cause a re hazard by drawing considerable
heat out of the rebox and into the space behind the noncombustible nish facing and from there up into the wall cavity behind
the drywall or other sheathing material that houses the Isokern replace.
Finish Facing Detail
Important: Grout
this gap with
Earthcore Mortar
to avoid creating
a “false chimney”.
Combustible
floor system
(non-insulation)
Hearth Extension
(Noncombustible)
Figure 29