AS 2082 (Visually stress-graded hardwood)
AS 2082:2007 sets the visual grading rules for hardwood structural timber. F-grade and species combinations, defects, grade stamps. The basis for sawn hardwood use.
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AS 2082:2007 is the Australian Standard for visually stress-grading hardwood for structural purposes. A trained grader inspects each piece of sawn hardwood and assigns an F-grade (F5, F7, F8, F11, F14, F17, F22, F27) based on slope of grain, knots, splits, splits, wane, and other visible defects. The F-grade combines with the species to determine allowable design loads under AS 1684 (residential timber framing) and AS 1720 (timber structures). Using ungraded hardwood as a structural member is non-compliant; the grade stamp is the documentary evidence the timber meets the standard.
Why builders care
Most residential timber framing in Australia uses machine-graded MGP10 / MGP12 / MGP15 softwood (radiata pine) under AS/NZS 1748. Hardwood (typically used for decking joists, bearers, exposed structural elements, heritage replacement) is visually graded under AS 2082, which is a different process producing different grade markings.
A builder spec’ing structural hardwood:
- Confirms F-grade required for the application from AS 1684 span tables.
- Specs species + F-grade combination to the timber supplier.
- Sights the grade stamp at delivery.
- Rejects pieces without stamps as non-compliant.
A piece of hardwood without an AS 2082 grade stamp is, for engineering purposes, ungraded and cannot be used structurally. Verifying the stamp at delivery is the cheapest QA in the chain.
What AS 2082 covers
| Element | What the Standard specifies |
|---|---|
| Grading rules | Visual criteria for slope of grain, knots, wane, splits, shakes, decay, insect attack |
| F-grades | F5 through F27 (eight grades, in ascending strength) |
| Species combinations | Which hardwood species can achieve which F-grades |
| Sample size, frequency | How graders sample and verify |
| Grade stamp format | What information the stamp must include |
F-grade and species
The F-grade is the stress grade, expressed as the basic bending strength in MPa (F8 = 8 MPa basic bending). Common Australian hardwood species and their typical F-grade range:
| Species | Typical F-grade range |
|---|---|
| Brushbox (Lophostemon confertus) | F11, F14, F17 |
| Spotted Gum (Corymbia maculata) | F14, F17, F22 |
| Ironbark (red, grey) | F17, F22, F27 |
| Blackbutt (Eucalyptus pilularis) | F11, F14, F17 |
| Tasmanian Oak (Eucalyptus regnans / obliqua) | F8, F11, F14 |
| Jarrah (Eucalyptus marginata) | F11, F14, F17 |
| Karri (Eucalyptus diversicolor) | F11, F17, F22 |
| Sydney Blue Gum (Eucalyptus saligna) | F11, F14 |
| Stringybark | F11, F14, F17 |
| Mountain Ash (Eucalyptus regnans) | F8, F11, F14 |
| Messmate (Eucalyptus obliqua) | F8, F11, F14 |
| Cypress pine (Callitris) | F5, F7 (soft hardwood) |
The species AND F-grade together determine allowable spans, fixings, and connection details.
The grade stamp
A compliant AS 2082 grade stamp typically shows:
- Mill identification.
- Species code (e.g. SPGM for spotted gum).
- F-grade (e.g. F17).
- Inspection authority code (often Forest and Wood Products Australia or state equivalent).
- AS 2082 reference.
Stamps are typically inked or branded onto the piece, usually near one end. They must be visible during installation; covering a stamp with sheeting before certifier inspection makes verification harder.
Common builder issues
- Builder specs hardwood by species only (“blackbutt”): supplier delivers F8 when F11 was required for the span. Frame inspection fails.
- No grade stamp visible: certifier rejects the timber.
- Mixed F-grades within a member group: the lowest grade governs the design for that group.
- Hardwood used structurally without F-grade reference: non-compliant; AS 1684 tables require F-grade.
- Machine-graded MGP softwood confused with visually-graded hardwood: different standards (AS/NZS 1748 vs AS 2082); different stamps; different design tables.
AS 1684 interaction
AS 1684 (residential timber framing) provides span tables keyed to F-grade AND species combinations. For a hardwood bearer of a particular span:
- Look up the AS 1684 hardwood span table.
- Identify the F-grade and species (or species group) that matches.
- Select the timber size accordingly.
The F-grade alone isn’t sufficient; species matters because density and stiffness vary even within an F-grade.
Where machine-graded MGP fits differently
Softwood structural timber in Australia is typically MGP10 / MGP12 / MGP15 (radiata pine), machine-graded under AS/NZS 1748. The grade designations are different:
| Standard | Grade designation | Timber |
|---|---|---|
| AS 2082 | F5-F27 | Visually graded hardwood |
| AS/NZS 1748 | MGP10, MGP12, MGP15 | Machine-graded softwood (typically pine) |
| AS/NZS 4063 | (variable) | Test-based grade verification |
AS 1684 span tables include separate sections for MGP softwood and F-grade hardwood. Use the right table for the right timber.
For builders
- Spec species + F-grade together when ordering hardwood: “Spotted gum F17, 240 x 45, 4.8 m, 6 lengths”.
- Sight every grade stamp at delivery: reject unstamped pieces.
- Match the AS 1684 span table to the timber: hardwood table for hardwood, MGP table for MGP softwood.
- Photograph the stamps at delivery: useful at frame inspection if the stamp gets covered later.
- Build a relationship with a quality timber merchant who reliably stamps every piece. Cheap unstamped timber is no saving.
References
-
AS 2082:2007 (purchase via SAI Global).
-
Forest and Wood Products Australia: https://www.fwpa.com.au (verified 2026-05-16).
-
Timber Queensland species and F-grade guidance: https://www.timberqueensland.com.au (verified 2026-05-16).
Related
See also
Last updated: 2026-05-16. Verified: 2026-05-16.