Specification
CORE GRADES (From Table 7 ©)
Grade Description J Grade K Grade L Grade M Grade
Thickness of Crossband Adjacent to Faces Any thickness
Thicker than
1/10"
1/10" and
thinner
Any thickness Any thickness
Knotholes and Other Round
Elliptical Openings (Max. Diameter)
None 3/8" 3/4" 1" 2 1/2"
Splits, Gaps and Other Elongated End or
Edge Openings — Visible on only one end or
edge of panel (Max. Width)
1/8" 1/4" 1/2" 1"
Hardwood Plywood Grading Guide 2015 columbiaforestproducts.com 25
ANSI/HPVA HP-1-2009 STANDARDS©
LIMITING CRITERIA FOR PLYWOOD (From Table 8 ©)
Limiting Factors TYPE 1 (EXTERIOR) TYPE 2 (INTERIOR)
Bond Line Requirements Fully waterproof Water resistant
Bond Line (glue bond) Test Performance Dry and cyclic-boil shear Three-cycle soak and dry
Grade and Limitations of Inner Plies Adjacent to Faces* K
K under AA, A or B
L under C, D or E
Grade of Other Inner Plies M or better M or better
NOTE: If the buyer requires a specic inner ply grade among those as listed in Table 7, it must be specied.
BACK GRADES (From Table 6 ©)
Grade Description 1 Back 2 Back 3 Back 4 Back
Sapwood Yes Yes Yes Yes
Discoloration & Stain Yes Yes Yes Yes
Mineral Streaks Yes Yes Yes Yes
Sound Tight Burls Yes Yes Yes Yes
Sound Tight Knots Max. diameter 3/8" Max. diameter 3/4" Max. diameter 1 1/2" Yes
Max. Number of Tight Knots 16 16
Unlimited to 1/2"; No more
than 16 from 1/2" to 1 1/2"
Unlimited
Knotholes No 1/2" Repaired 1" 4"
Max. Combined Number of
Knotholes and Repaired Knots
None
All repaired;
Unlimited to 3/8"; No more
than 8 from 3/8" to 1/2"
Unlimited to 3/8"; No more
than 10 from 3/8" to 1"
Unlimited
Wormholes Filled Filled Yes Yes
Splits or Open Joints Six 1/8" x 12" repaired Six 3/16" x 12" repaired
Yes, 3/8" x 1/4" Length of
Panel (LOP)
1" to 1/4 LOP,
1/2" to 1/2 LOP,
1/4" to Full LOP
Doze & Decay Firm areas of doze Firm areas of doze Firm areas of doze
Areas of doze and decay
provided serviceability of
panel is not impaired
Rough Cut/Ruptured Grain Two 8" diameter areas 5% of panel Yes Yes
Bark Pockets 1/8" wide repaired 1/4" wide repaired Yes Yes
Laps No Repaired Yes Yes