Raw plywood grades
The quality grade of plywood is defined by type and quantity of visible defects, measured by EN 635-5.
Riga Ply grading conditions are in compliance or stricter in comparison with requirements set by the following regulatory documents:
- EN 635-2 Plywood - Classification by Surface Appearance – Part 2. Hardwood;
- SFS 2413 quality requirements for appearance of plywood with outer plies of birch;
- ISO 139 Recommendations and Conditions Drawn by Work Group II of the Technical Committee (1994).
| Grade | Recommended application | |
|---|---|---|
| S | For good quality staining and lacquering. Total number of defects ≤ 6 |  |
| BB | For finishing and coating with transparent and non-transparent thicker overlays and films, veneering and applications where a solid face is required. Total number of defects ≤ 9 |  |
| WG | For use where surface appearance is not important, reverse grade. The total number of defects is unlimited |  |
| WGE | Plywood of WG grade without open defects (repaired with filler), for overlaying with non-transparent finishing material. |  |
| Grade | Recommended application |
|---|---|
| S | For good quality staining and lacquering. Total number of defects ≤ 6 |
|
|
|
| BB | For finishing and coating with transparent and non-transparent thicker overlays and films, veneering and applications where a solid face is required. Total number of defects ≤ 9 |
|
|
|
| WG | For use where surface appearance is not important, reverse grade. The total number of defects is unlimited |
|
|
|
| WGE | Plywood of WG grade without open defects (repaired with filler), for overlaying with non-transparent finishing material. |
|
|
|
Categories of defects
- Permitted
- Not permitted
| DEFECT | PLYWOOD GRADES | ||
|---|---|---|---|
| S | BB | WG | |
| Closed splits and checks | |||
|
For an individual max length up to 200 mm and not more than 2 per meter of panel width |
For an individual max length up to 200 mm and not more than 2 per meter of panel width |
|
| Coloured streaks | |||
|
Slightly |
||
| Coloured streaks, brown, but not rot | |||
|
Up to 30% of the surface area |
||
| Composed face veneers | |||
|
If composed properly, conformable colour |
||
| Curly grain | |||
|
|||
| Defects at the edges caused by the sanding or trimming | |||
|
Up to 5 mm from the edge, not in whole length |
Up to 5 mm from the edge, not in whole length |
Up to 5 mm from the edge |
| Glue penetration | |||
|
If occasionally |
Up to 5% of the surface area |
|
| Imprints and bumps | |||
|
Slightly, up to 2 cm² per panel |
Slightly |
|
| Inserts | |||
|
If properly inserted and match the plywood colour, not more than 1/m² |
Up to 3% of the surface area |
|
| Irregularities in the structure of the wood | |||
|
|||
| Open joints | |||
|
Up to an individual max width 2 mm and individual max length 200 mm, not more than 1 per meter of panel width, repaired with putty |
Up to an individual max width 3 mm |
|
| Open splits and checks | |||
|
For an individual max width up to 4 mm, not more than 2 per meter of panel width |
||
| Open splits and checks, repaired by putty | |||
|
For an individual max width up to 2 mm and for an individual max length up to 200 mm, not more than 1 per meter of panel width |
For an individual max width up to 2 mm and for an individual max length up to 200 mm, not more than 1 per meter of panel width |
For an individual max width up to 4 mm, not more than 2 per meter of panel width |
| Other knots and holes | |||
|
Up to an individual max Ø 6 mm, if the cumulative Ø does not exceed 25 mm/m² |
Up to an individual max Ø 15 mm, if the cumulative Ø does not exceed 100 mm/m² |
|
| Overlap | |||
|
|||
| Pin knots | |||
|
|||
| Roughness | |||
|
Slightly, up to 10 cm²/m², if repaired with putty – max 3 defects per panel |
||
| Sanding through | |||
|
≤ 10 cm²/m² |
≤ 20 cm²/m² |
|
| Sound intergrown knots | |||
|
Up to an individual max Ø 20 mm, if the cumulative Ø does not exceed 50 mm/m² |
Up to an individual max Ø 25 mm, if the cumulative Ø does not exceed 60 mm/m² |
Up to an individual max Ø 65 mm, if the cumulative Ø does not exceed 600 mm/m² |
| Unsanded areas | |||
|
Up to an extent of 5% of the panel surface |
||
| Unsound adhering knots | |||
|
Up to an individual max Ø 20 mm, if the cumulative Ø does not exceed 200 mm/m² |
||
| Wood discolouration | |||
|
Slightly |
Up to 30% of the surface area |
|
| Total number of defects | |||
| ≤ 6 | ≤ 9 | Unlimited | |
| PLYWOOD GRADES | ||
|---|---|---|
| S | BB | WG |
| DEFECT | ||
| Closed splits and checks | ||
For an individual max length up to 200 mm and not more than 2 per meter of panel width |
For an individual max length up to 200 mm and not more than 2 per meter of panel width |
|
|
|
||
| Coloured streaks | ||
Slightly |
||
|
|
||
| Coloured streaks, brown, but not rot | ||
Up to 30% of the surface area |
||
|
|
||
| Composed face veneers | ||
If composed properly, conformable colour |
||
|
|
||
| Curly grain | ||
|
|
||
| Defects at the edges caused by the sanding or trimming | ||
Up to 5 mm from the edge, not in whole length |
Up to 5 mm from the edge, not in whole length |
Up to 5 mm from the edge |
|
|
||
| Glue penetration | ||
If occasionally |
Up to 5% of the surface area |
|
|
|
||
| Imprints and bumps | ||
Slightly, up to 2 cm² per panel |
Slightly |
|
|
|
||
| Inserts | ||
If properly inserted and match the plywood colour, not more than 1/m² |
Up to 3% of the surface area |
|
|
|
||
| Irregularities in the structure of the wood | ||
|
|
||
| Open joints | ||
Up to an individual max width 2 mm and individual max length 200 mm, not more than 1 per meter of panel width, repaired with putty |
Up to an individual max width 3 mm |
|
|
|
||
| Open splits and checks | ||
For an individual max width up to 4 mm, not more than 2 per meter of panel width |
||
|
|
||
| Open splits and checks, repaired by putty | ||
For an individual max width up to 2 mm and for an individual max length up to 200 mm, not more than 1 per meter of panel width |
For an individual max width up to 2 mm and for an individual max length up to 200 mm, not more than 1 per meter of panel width |
For an individual max width up to 4 mm, not more than 2 per meter of panel width |
|
|
||
| Other knots and holes | ||
Up to an individual max Ø 6 mm, if the cumulative Ø does not exceed 25 mm/m² |
Up to an individual max Ø 15 mm, if the cumulative Ø does not exceed 100 mm/m² |
|
|
|
||
| Overlap | ||
|
|
||
| Pin knots | ||
|
|
||
| Roughness | ||
Slightly, up to 10 cm²/m², if repaired with putty – max 3 defects per panel |
||
|
|
||
| Sanding through | ||
≤ 10 cm²/m² |
≤ 20 cm²/m² |
|
|
|
||
| Sound intergrown knots | ||
Up to an individual max Ø 20 mm, if the cumulative Ø does not exceed 50 mm/m² |
Up to an individual max Ø 25 mm, if the cumulative Ø does not exceed 60 mm/m² |
Up to an individual max Ø 65 mm, if the cumulative Ø does not exceed 600 mm/m² |
|
|
||
| Unsanded areas | ||
Up to an extent of 5% of the panel surface |
||
|
|
||
| Unsound adhering knots | ||
Up to an individual max Ø 20 mm, if the cumulative Ø does not exceed 200 mm/m² |
||
|
|
||
| Wood discolouration | ||
Slightly |
Up to 30% of the surface area |
|
|
|
||
| Total number of defects | ||
| ≤ 6 | ≤ 9 | Unlimited |