Heat & Glo MEZZO36-C Installation Manual page 58

This section discusses installation details associated
with the Inside and Overlap Fit methods and specifies
additional non-combustible materials required.
When finishing the wall around the fireplace, it is critical
that wall sheathing be fastened properly. Wall sheathing
fasteners, such as screws or nails, are not permitted in
some locations. See Figure 10.1.
It is acceptable to pre-drill holes and use self-tapped
screws in the factory-included non-combustible board
which may be used to lathe (a backer for tile, marble,
etc.). Screws being installed through the installed non-
combustible board should be self-tapping type with a
maximum length of 2 inches. See Figure 10.1.
When installing finish material on the lower cover panel,
DO NOT drill or install screws longer than 3/4 of an inch.
Screws longer than 3/4 of an inch could penetrate the
lower cover panel causing damage to components or
penetrate the gas line. See Figure 10.1.
WARNING! Risk of Fire! DO NOT use screws longer
than two inches when attaching finishing materials to in-
stalled non-combustible material. Screws longer than two
inches will compromise clearance and could cause over-
heating and fire.
WARNING! Risk of Fire, Explosion or Asphyxiation!
DO NOT use screws more than 3/4 of an inch long on
lower cover panel. Longer screws may penetrate gas line
or damage valve or electrical components.
MAXIMUM SCREW LENGTH = 2 INCHES
(INSTALLED NON-COMBUSTIBLE BOARD)
NON-COMBUSTIBLE MATERIAL
ONLY IN THIS AREA
MAXIMUM SCREW LENGTH = 3/4 INCH
(LOWER COVER PANEL)
= NO FASTENERS IN THIS AREA
Note: It is acceptable to use a high temperature silicone
sealant to adhere drywall to lower cover panel.
Figure 10.1 Screw Length Requirements
The appliance is designed to mate with 1/2 in. wall
sheathing materials such as drywall, plywood, wood
composites, or non-combustible materials.
58 Heat & Glo • MEZZO36-C/ST-C, MEZZO48-C/ST-C, MEZZO60-C/ST-C, MEZZO72-C/ST-C Installation Manual • 2600-980 Rev. D • 9/19
Finish and Sealing Joints
All joints between the finished wall sheathing and the ap-
pliance must be sealed with non-combustible materials.
Sealants, such as caulk or mastic used to seal the gap
between the wall and the fireplace, should be rated at a
minimum continuous exposure to 300 ºF.
Finishing Around Opening with Gypsum Wallboard
Gypsum wallboard (drywall) joints adjacent to the fire-
place opening, including the non-combustible board on
the appliance, require special attention to minimize crack-
ing. When installing gypsum wallboard around the fire-
place, install the hole for the fireplace opening in a single
wallboard sheet, if possible. This will minimize the joints
adjacent to the fireplace opening.
Tape wall board joints around the fireplace opening with
fiberglass-mesh tape. It will provide a more crack-resis-
tant joint than paper tape. Fill, smooth and finish wall
joints with chemically setting-type joint compound. It will
provide a more crack-resistant joint than air-drying light-
weight compound.
Painting
If desired finishing includes a painted wall, 100% acrylic
latex with compatible primer is recommended around this
appliance. Oil-based or standard acrylic paints may dis-
color due to heat exposure.
In extreme cases, lab tests have shown yellow pigments
fading out of paints over time due to heat. Vent run and
installation location will have an effect on wall temperature
and fading. If fading occurs, consider avoiding paint that
contains yellow pigment.
In regards to the sheetrock mud, apply a smooth, even
layer, covering a wide area of the wall for the best results.
For best results, follow the tips below.
To Reduce the Risk of Sheetrock Cracking:
Use all purpose joint
compound.
Use eggshell paint
(100% acrylic latex paint, gloss or semi-gloss).
2 IN.
Use a quick set or light weight joint compound.
Use flat paint.
If a crack does emerge adjacent the fireplace, it can
be permanently repaired by filling it with paintable latex
caulk, followed by repainting.
WARNING! Risk of Fire! DO NOT apply combustible
materials beyond the minimum clearances. Comply with
all minimum clearances to combustibles as specified in
this manual. Materials overlapping into non-combustible
zones could ignite and will interfere with air flow through
decorative barrier fronts.
WARNING! Risk of Fire! DO NOT install drywall or other
combustible materials directly onto the installed non-
combustible board. Overlapping materials could ignite.
DO
To Avoid Sheetrock Cracking:
DO NOT