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Planning
Cracking wall finishes
The HeatShift system reduces the wall temperatures
and minimizes the possibility of cracking wall fi nishes.
If a clean fi nish with no tile, etc. is desired, joints in the
cement board and the transition to gypsum board
will require special attention if future cracking is to be
controlled. Be aware that temperatures on the non-
combustible wall surface above the appliance can
exceed 175°F.
Below are some tips on how to best avoid any cracking:
• Allow materials to dry thoroughly before fi nishing
the wall. Cement board has the ability to absorb up
to 30 percent of its weight in water and may shrink as
much as 1/8" over a 48" length when drying from a
saturated condition. Running the fi replace before fi nal
fi nishing will help drive out moisture.
• Always pre-drill screw holes through cement board
and use screws with self-milling head.
• Always use tape over joints.
• Behind joints, double up studs or use studs "on the
fl at" to add extra support to the joint. Adhesive on
the backside of wall board behind any joints can help
control diff erential movement.
• Use multiple, thinner coats of joint compound and al-
low to dry thoroughly between coats.
• Ensure framing materials are dry.
• After fi nishing the wall, introduce heat gradually to
slowly dry any excess moisture rather than drying too
fast.
• Avoid notching cement board or tiles around corners
of window opening and instead provide a joint that
intersects the corner.
18
Wall Finish
Cracks
Provide joints
either here or
here
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