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Panel Strength & Bending Stiffness

Comparison of APA’s Structural OSB Panels 

Structural I’ on an APA trademark for OSB sheathing and Sturd-I-Floor indicates that it is a performance-rated panel, compared to basic rated panels. It also denotes that it meets the specific requirements of US Performance Standard PS 2 for cross-panel strength and stiffness in bending and racking load performance.

The further the supports are spaced, the thicker the panel may have to be. Our comparison tables below show the superior bending stiffness and strength for OSB Structural I sheathing and Sturd-I-Floor. Click on the link you need.  For more technical information on span ratings and performance categories for OSB panels, see here .

Roof and subfloor sheathing:  comparing OSB Rated Structural 1 panel and basic OSB Rated Sheathing

Flooring: comparing OSB Structural I panel with with basic OSB Rated Sturd-I-Floor

Bending Stiffness Comparison, Sheathing

STRESS APPLIED PARALLEL TO STRENGTH AXIS1 STRESS APPLIED PERPENDICULAR TO STRENGTH AXIS1 SPAN RATING PERFORMANCE CATEGORY PREDOMINANT THICKNESS LABEL
Rated Sheathing Structural I Sheathing Rated Sheathing Structural I Sheathing
60,000 60,000 11,000 17,600 Roof-24 3/8 0.354 IN
78,000 78,000 16,000 25,600 Roof-24 Subfloor-16 7/16 0.418 IN
115,000 115,000 25,000 40,000 Roof-32 Subfloor-16 15/32 0.451 IN
225,000 225,000 56,000 89,600 Roof-40 Subfloor-20 19/32 0.578 IN
400,000 400,000 91,500 146,600 Roof-48 Subfloor-24 23/32 0.704 IN
Note:¹ The strength axis is parallel to the face and back orientation of the strands unless   otherwise indicated.
Bending Strength F S (lb-in²/ft of panel width) 

STRESS APPLIED PARALLEL TO STRENGTH AXIS1 STRESS APPLIED PERPENDICULAR TO STRENGTH AXIS1 SPAN RATING PERFORMANCE CATEGORY PREDOMINANT THICKNESS LABEL
Rated Sheathing Structural I Sheathing Rated Sheathing Structural I Sheathing
300 300 97 145.5 Roof-24 3/8 0.354 IN
385 385 115 172.5 Roof-24 Subfloor-16 7/16 0.418 IN
445 445 165 247.5 Roof-32 Subfloor-16 15/32 0.451 IN
750 750 270 405 Roof-40 Subfloor-20 19/32 0.578 IN
1,000 1,000 405 607.5 Roof-48 Subfloor-24 23/32 0.704 IN
Note: 1   The strength axis is parallel to the face and back orientation of the strands unless otherwise indicated.
  Sturd-I-Floor comparisons – OSB Bending Stiffness EI (lb-in²/ft of panel width) 

STRESS APPLIED PARALLEL TO STRENGTH AXIS1 STRESS APPLIED PERPENDICULAR TO STRENGTH AXIS1 SPAN RATING PERFORMANCE CATEGORY PREDOMINANT THICKNESS LABEL
Rated Sheathing Structural I Sheathing Rated Sheathing Structural I Sheathing
150,000 150,000 34,000 54,400 16 oc 19/32 0.578 IN
210,000 210,000 40,500 64,800 20 oc 19/32 0.578 IN
300,000 300,000 80,500 128,800 24 oc 23/32 0.704 IN
650,000 650,000 235,000 376,000 32 oc 7/8 0.849 IN
1,150,000 1,150,000 495,000 792,000 48 oc 1-1/8 0.1.091 IN
Note:1   The strength axis is parallel to the face and back orientation of the strands unless otherwise indicated.
Bending Strength F S (lb-in²/ft of panel width)

STRESS APPLIED PARALLEL TO STRENGTH AXIS1 STRESS APPLIED PERPENDICULAR TO STRENGTH AXIS1 SPAN RATING PERFORMANCE CATEGORY PREDOMINANT THICKNESS LABEL
Rated Sheathing Structural I Sheathing Rated Sheathing Structural I Sheathing
500 500 180 270 16 oc 19/32 0.578 IN
575 575 250 375 20 oc 19/32 0.578 IN
770 770 385 577.5 24 oc 23/32 0.704 IN
1,050 1,050 685 1,027.5 32 oc 7/8 0.849 IN
1,900 1,900 1,200 1,800 48 oc 1-1/8 0.1.091 IN
Note:The strength axis is parallel to the face and back orientation of the strands unless otherwise indicated.