Specification

“Performance in the Real
World
vs.
A Controlled Laboratory”
Thermo-ply
®
outperforms other sheathing
products which claim to deliver extra R-values.
One of the most important
factors to consider is the
sheathing’s ability to do its
basic job of controlling heat
loss or gain caused by air
moving or infiltrating through
the walls into the insulation.
Thermo-ply retains a much
larger percentage of the
wall system’s R-value than
other sheathing products,
which can lose over 50% of
the R-value in only a 10 mph
breeze.
The percentages show the retained, effective R-
value for wall sections built with all components
being the same EXCEPT the sheathing. This sum-
mary on effective R-values is based on air infil-
tration tests run by an independent laboratory
with industry accepted methods (ASTM E-283),
and further supported by the 1984 Department
of Energy report.*
The total static R-value for a Thermo-ply sheath-
ing system is a combination of the R-value of
Thermo-ply itself and that of the reflective airspace
between the sheathing and the siding. The chart
on page 7 shows the total R-value resulting from
both of these factors for various airspace sizes, us-
ing typical siding components.
1
“Affordable Manufactured Housing Through Energy Conservation,” U.S. Depart. of Energy (DOE), July 1984.
2
R-values of wall sections include aluminum siding, sheathing gypsum, airspace, air films, and an assumed R-13 kraft-faced
batt insulation. Note: R-value means resistance to heat flow. The higher the R-value the greater the insulating power.
R-Value Analysis
1, 2
Sheathing
Calculated or
Static “R” With-
out 10 mph Wind
Effective “R” When
exposed to Simu-
lated 10 mph Wind
Percentage of
Retained Effec-
tive R-value
Thermo-ply
1” Dow Foam (Styrofoam
tm
)
1” Foil -Faced Urethane Foam
1” EPS Foam
1
/
2” Fiberboard
15.6
20.0
23.4
18.67
15.99
11.8
11.3
10.5
10.8
8.15
75.6%
56.5%
44.9%
57.8%
51.0%