All quality grades
Wane, i.e. bark on the timber, is permitted on non-visible parts of the timber that do not affect its visual appearance, for example on the underside of the timber or on the tongue.
Other timber defects and quality-determining parameters not described above are considered acceptable or may be agreed individually.
- Non-through checks not exceeding 50 mm in length are permitted.
- For pine timber, minor resin pockets up to 10 mm in length are permitted.
Grade I
A slightly lower quality grade.
- Moisture content: 8–12 %.
- Knots are permitted — the size of sound (live) knots is not restricted.
- Black (dead) knots are permitted up to 15 mm.
- Loose (fallen-out) knots are permitted up to 8 mm.
- Non-through checks are permitted.
- For pine timber, resin pockets up to 25 mm in length are permitted.
Grade II
The lowest quality grade.
- Moisture content: 8–12 %.
- Knots of unlimited size are permitted.
- Black (dead) knots and loose (fallen-out) knots may be present.
- Non-through checks are permitted.
- Through splits up to 300 mm in length are permitted.
- For pine timber, resin pockets of unlimited size are permitted.
Exterior cladding timber
For exterior cladding boards and other timber intended for outdoor use, two main quality grades are distinguished.
AB quality
- Moisture content: 18–20 %.
- Knots are permitted — the size of sound (live) knots is not restricted.
- Black (dead) knots are permitted up to 20 mm.
- Loose (fallen-out) knots are permitted up to 10 mm.
- Non-through checks are permitted.
- Resin pockets are permitted up to 50 mm in length.
C quality
- Moisture content: 18–20 %.
- Knots of unlimited size are permitted.
- Black (dead) knots and loose (fallen-out) knots may be present.
- Non-through checks are permitted.
- Through splits up to 300 mm in length are permitted.
- Resin pockets of unlimited size are permitted.