Technical Considerations
Thermo-ply has been extensively tested in all areas of installed performances by independent laboratories. Here are some of the findings.
New 1-hour fire rating.
Now, Structural Grad (red) and Super Strength Grade (blue) Thermo-ply Insulative Wall Sheathings are approved materials for a 1-hour fire-rated wall system. Independently tested at Ohio State University's Building Material Research Laboratory, the wall system demonstrated a Fire Endurance Classification of 1 hour. The fire rating chart below shows test wall construction and other accepted wall systems.
The load-bearing wall system was tested with an 1800-lb. load which realistically simulated real-world conditions. It was constructed with Thermo-ply sheathing and tested in accordance with the Standard Methods of Fire Tests of Building Construction and Materials using ASTM E-119 testing procedures.
Thermo-ply wall sheathing passed. And, coupled with its successful resistance to flame spread, Thermo-ply now does even more to help you sell homes. And Thermo-ply does it without combustibility warnings or worries of toxic fumes.
Racking and shear strength.
The strength of a sheathing material is commonly measured by RACKING RESISTANCE, which can be converted to shear strength.
Thermo-ply offers the superior racking resistance and shear strength to meet or exceed most tough building codes, and can be substituted for plywood in most areas when lightweight, durable, easy handling is desired.
Contact Southern California Distribution (formerly Landmark Building Products) for racking and shear strength comparisons with plywood and 1" x 4" corner bracing as used in your area. Also contact us for regional code regulations of racking and shear values.
Wind force resistance safety.
Forces created by wind must be absorbed by the walls and foundation running parallel to the wind. In calculating the shear strength of a wall system, the short walls (generally the side walls) are considered the shear walls because the greatest force will be generated on the long walls. These forces will be resisted by the short walls. Significant safety factors are obtained when using Thermo-ply.
Permeability and condensation facts.
In over 30 years of use, Thermo-ply has been applied in climatic regions of the United States with no condensation problems, provided it has been properly installed with an effective barrier on the warm side of the wall.
When vapor barrier systems are installed properly, condensation will not occur under normal living conditions.
All sheathing materials leak air. While Thermo-ply sheathing is the tightest we've tested, there is enough leakage to produce air change in the wall cavity every 136 minutes in 10-mph wind, and every 70 minutes in 15-mph wind. This air movement will help remove moisture from the wall cavity should it occur.
Note: Exterior grade plywood, used as a sheathing in some areas, has a perm rating of 0.6 and Thermo-ply is in that range.
Test Wall with 1-Hour Fire Rating
Plywood Siding
A. 5/8" Type X Gypsum Wallboard
B. 2 x 4 Wood Stud 16" o.c. 1800# per Stud
C. R-13* Friction-Fit Glass Fiber Insulation
D. Fire Exposure on the Interior Face per ASTM E-119
E. 0.113" Thick Thermo-ply Stormbrace Sheathing
F. 19/32" Thick Group 1 Exterior Plywood Panel Siding
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Hardboard Siding
A. 5/8" Type X Gypsum Wallboard
B. 2 x 4 Wood Stud 16" o.c. 1800# per Stud
C. R-13* Friction-Fit Glass Fiber Insulation
D. 0.113" Thick Thermo-ply Stormbrace Sheathing
E. Hardboard Siding. Solid Wood or Plywood to 11/32" Thick
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Aluminum Siding
A. 5/8" Type X Gypsum Wallboard
B. 2 x 4 Wood Stud 16" o.c. 1800# per Stud
C. R-13* Friction-Fit Glass Fiber Insulation
D. 0.113" Thick Thermo-ply Stormbrace Sheathing
E. Aluminum Siding** or Steel
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Brick Veneer
A. 5/8" Type X Gypsum Wallboard
B. 2 x 4 Wood Stud 16" o.c. 1800# per Stud
C. R-13* Friction-Fit Glass Fiber Insulation
D. 0.113" Thick Thermo-ply Stormbrace Sheathing
E. Brick Veneer, Stone or Stucco Exterior Finish
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* R-11 insulation may be substituted.
**With or without backing board.
As shown above, the test wall was constructed of standard building materials and the interior side of the wall was exposed to flames. The test wall was sided with exterior plywood paneling, although aluminum and steel siding, hardboard, solid wood and plywood siding, brick veneer, stone, and stucco are also approved siding materials.
"Meets BOCA & SBCCI one hour fire rating standards. For ICBO compliance information in your area, check with your local building officials."
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