85-03-01058-O
FV33i Gen 3
Page
32
3.2.16
Suitable Mantel, Facing & Hearth Pad Materials
Materials used in areas designated as non-combustible must be rated as non-combustible per NFPA 220 Standard on Types of
Building Construction, or reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube
Furnace at 750 Degrees C.
WARNING: Common Finishing Materials Not Approved for use.
Paper faced gypsum board (drywall) including Type X Fire Rated board is not a non-combustible material. These boards are
not approved for use in the non-combustible zone of the insert.
WonderBoard brand boards are commonly used as a backerboard for tile. WonderBoard backerboard is not a non-
combustible material and is not approved for use in the non-combustible zone of the insert. In addition, WonderBoard off-
gasses when heated and should not be used anywhere near the insert.
Information for common materials used is given below. Mendota does not guarantee any materials used around the insert.
Mendota disclaims any and all liability for any damage to finishing materials including warping, discoloring, cracking, peeling or
flaking. This also includes any off-gassing or unpleasant smells from materials when they are heated.
R-Values of Common Finishing Materials
R-Values of Hearth Pad Boards
Material
Thickness
R-Value
Application
Mineral Fiber Board (Micore 160, 300, SB)
1/2"
1.2 – 1.4
Only approved for use as an insulator
under other non-combustible finishing
material for a hearth pad.
Cearmic Board (Rescor 360)
1/2"
1.11
Cearmic Board (Fiberfrax Duraboard LD)
1/2"
1.10
R-Values of Common Finishing Materials
Material
Thickness
R-Value
Application
SkamoEnclosure Board
1”
0.410
Best option for a smooth wall finish. Least chance
of cracking from heat.
Promat Promafour
1”
0.410
Cement Board (Hardibacker 500)
1/2"
0.200
Best used as a backer board for tile or natural
stone installations.
Not recommended as a smooth wall finish.
Cement Board (Hardibacker)
1/4"
0.130
Common Brick
2-1/4"
0.450
Common non-combustible materials used around
an insert. Can be used on the wall or hearth pad.
Install these materials per the recommendations
in the following sections.
Common Brick
4"
0.800
Thinset Mortar
1/4"
0.100
Concrete (150 lbs/Cubic Foot)
1"
0.07
Ceramic Tile
1/4"
0.25
Flagstone
1"
0.079
Granite
1"
0.05
Limestone
1"
0.08
Marble
1"
0.08
Sandstone
1"
0.079
Slate
1"
0.100
