Hearthstone Quality Home Heating Products, Inc.
®
Homestead Models #8570F and #8570H
10
A floor protector with an R-value of 6.6 or more
that you obtain from your dealer. (A floor
protector is any noncombustible on the floor
underneath and extending to the front, sides,
and rear of the wood stove.)
Install your Freestanding stove with 6” legs with the
floor heat shield on one of the following:
A hearth pad listed to UL 1618 standards. These
are noncombustible floor protectors; no other
type of floor protector is acceptable.
A composite (homemade) floor protector with an
R-value of 2.5 or more.
The hearth pad or floor protector must measure at
least 41”w x 41”d square (1041mm x 1041 mm).
Place your stove so that the floor protector extends
16 inches (450 mm), [18 inches in Canada] to the
front and centered beyond each side of the fuel
loading and ash removal openings (as illustrated,
looking down onto the top of the stove).
Figure 1 – Hearth Dimensions (US)
Regardless of where your stove is installed, the area
extending at least 16 inches in front of the stove
must have an insulating R-value of 2.5; you can also
use a listed floor protector for this area. This
provides floor protection in front of the loading door.
You must also place floor protection under the
chimney connector, extending 2” (50 mm) beyond
each side.
Floor protector’s come with various types of
specifications. To convert a floor protector’s
specification to an R-value, do one of the following:
If the R-value is given, use that value—no
conversion is needed.
If a K-factor is given with a required thickness
(T) in inches, use this formula: R-value = 1/K x T
If a C-factor is given, use the formula: R-value =
1/C
To determine the R-value of the proposed alternate
floor protector:
Use either the K-factor or the C-factor formula
explained above to convert specifications not
expressed as R-values.
For multiple layers of floor protectors, simply add
the R-values of each layer to determine the
overall R-value of the layers.
If the overall R-value of your setup is greater than
the R-value of the specified floor protector, then your
setup is acceptable.
Fabricating a Homemade Floor Protector
You can make your own floor protector by stacking
together noncombustible materials from the
following table. Simply add together the listed
R-values to attain the necessary requirements for
installing your stove.
Noncombustible Material
Thickness
R-value
Gypsum or plaster board
1
1
/
2
” 0.45
Wallboard, Wonderboard, or
Durock
1
1
/
2
”
0.20
Ceramic board (Fiberfrax or
Micor)
1
1
/
2
” 1.10
Nominal solid clay brick
1
1”
0.20
Ceramic wall or floor tile
1
1
/
4
” 0.01
Mineral wool insulation
2
1”
3.12
Cement mortar
2
1”
0.20
Horizontal still air
2
*
1
/
8
” 0.92
Note: You cannot “stack” horizontal still air
to accumulate R-values; you must separate
each layer of horizontal still air with another
noncombustible material.
To fabricate a floor protector for a wood floor with an
R-value of at least 2.5, consider the following
examples:
½” ceramic board
1.10
8
” horizontal still air
0.92
4” solid clay brick
0.80
1
Check manufacturer’s specifications
2
According to ASHRAE Handbook of Fundamentals 1977
