Plywood Grades

 

U.S. Product Standard PS 1—Construction of Industrial Plywood  

1995 APA, 2009 APA

all-veneer panels/plywood

 

1. prescriptive specification - how to make plywood
2. performance standard - load capacity, dimensional stability, moisture

 

Performance Rated Panels - APA

Structural Plywood - 2009 NIST

Engineered Wood Construction Guide - 2011 APA

 

 

Sanded Panels

reduced thickness

different cross-sectional properties in strength calculations

 

grade stamp

  1. veneer grade of face and back
  2. minimum species group of face and back
  3. exposure durability classification
  4. product standard
  5. mill number
  6. qualified inspection and testing agency
source

Grades and Specifications - APA

 

 

Sheathing Grades

roof, floor, wall

 

C-C  (exterior)
C-D  (exposure 1)

C-C STR I
C-D STR I

grade stamp

  1. veneer grade of face and back
  2. minimum species group of face and back
  3. exposure durability classification
  4. product standard
  5. mill number
  6. qualified inspection and testing agency
  7. thickness
  8. span rating
source

examples

 

 

Span Rating

1. max. recommended span as roof sheathing
2. max. recommended span as subflooring

 

no need for structural calculations

 

assumptions

  1. continuous over two or more spans
  2. strong direction
  3. edge support requirements

 

ASD/LRFD Manual table M9.1-1
IBC table 2304.7(3)

 

 

Thickness

different thicknesses for same span

Panel Design Specification - APA table 5
usually minimum thickness is available

 

sheathing loads - minimum span rating
diaphragm loads - minimum panel thickness