Building Products Glossary
Plain-language definitions for the terms you'll meet across Australian construction — engineered timber grades, bushfire BAL ratings, treatment classes, plywood specs, and the AS/NZS standards behind them.
50 terms
Engineered Grades
- MGP10 Machine-graded pine stress grade used widely in Australian residential wall framing, with characteristic bending strength of 17 MPa and modulus of elasticity around 10 GPa.
- MGP12 Higher-stiffness machine-graded pine used where longer spans or stiffer floor and roof framing are required, with modulus of elasticity around 12 GPa.
- F7 Visually graded structural timber stress grade with characteristic bending strength of approximately 7 MPa, used for light framing and general structural applications.
- F17 Mid-strength hardwood stress grade with approximately 17 MPa characteristic bending strength, common for hardwood framing, beams, and structural plywood face veneers.
- F27 High-strength hardwood stress grade with approximately 27 MPa characteristic bending strength, used for heavy structural members and exposed-feature beams.
- GL13 Glue-laminated timber stress grade with characteristic bending strength of about 33 MPa and modulus of elasticity of approximately 13 GPa, used in residential beams and posts.
- GL17 Mid-tier glue-laminated timber grade with approximately 17 GPa modulus of elasticity, suitable for longer spans and higher-load structural beams.
- GL18 High-grade hardwood glulam with approximately 18 GPa modulus of elasticity, used where maximum strength and stiffness are required from a laminated section.
- LVL E13.2 Laminated Veneer Lumber with a characteristic modulus of elasticity of 13.2 GPa, used as a high-performance, dimensionally stable structural beam and joist material.
Treatment Grades
- H2 Treatment Preservative treatment level for interior framing protected from weather, designed to resist termite and borer attack in dry, above-ground conditions.
- H3 Treatment Preservative level for outdoor, above-ground timber exposed to the weather but not in soil, suitable for cladding, fascia, pergolas, and decking boards.
- H4 Treatment Preservative level for in-ground timber exposed to severe decay and termite hazard, used for fence posts, retaining walls, and landscape timbers.
- H5 Treatment Heavy-duty preservative level for critical in-ground timber, including house stumps, retaining walls, and poles where failure would have major consequences.
- LOSP Light Organic Solvent Preservative system that delivers H2 or H3 protection without the swelling associated with water-borne treatments, keeping dressed sections stable.
- CCA Copper Chrome Arsenate, a long-established water-borne wood preservative effective in H3, H4, H5, and H6 hazard environments and recognised by its green tint.
- ACQ Alkaline Copper Quaternary, an arsenic-free water-borne preservative used for H3 and H4 timber where human contact or environmental sensitivity rules out CCA.
- Copper Azole Modern arsenic-free water-borne preservative using copper plus organic azole co-biocides, certified for H3 to H5 environments and widely used for treated pine decking.
Bushfire (BAL)
- BAL-12.5 Lowest assessed Bushfire Attack Level under AS 3959, corresponding to a radiant heat flux of up to 12.5 kW/m squared and limited ember attack risk.
- BAL-19 Bushfire Attack Level for sites with predicted radiant heat flux up to 19 kW/m squared, requiring increased ember protection and limited material restrictions.
- BAL-29 Bushfire Attack Level for sites with predicted radiant heat flux up to 29 kW/m squared, where ember attack and significant radiant heat both threaten the building.
- BAL-40 High-risk Bushfire Attack Level for sites with radiant heat flux up to 40 kW/m squared and increased likelihood of direct flame contact during a fire.
- BAL-FZ Most severe Bushfire Attack Level, the Flame Zone, where radiant heat flux exceeds 40 kW/m squared and direct flame contact is expected during a bushfire.
Australian Standards
- AS 3959 Australian Standard governing the construction of buildings in bushfire-prone areas, defining the BAL system and material requirements for each level.
- AS 1684 Australian Standard for residential timber-framed construction, providing span tables and bracing rules for Class 1 and Class 10 buildings up to two storeys.
- AS/NZS 1748 Joint Australian and New Zealand Standard for the mechanical stress grading of timber, underpinning the MGP grade system used in Australian framing.
- AS/NZS 2269 Joint Australian and New Zealand Standard for structural plywood, defining bond, veneer quality, stress grades, and product marking for engineered plywood applications.
- AS/NZS 2272 Joint Australian and New Zealand Standard for marine plywood, defining premium veneer quality and Type A bond for use in boatbuilding and severe wet exposure.
- AS 1720 Australian Standard for the engineering design of timber structures, providing characteristic properties and design methods for sawn timber, glulam, LVL, and plywood.
- AS/NZS 1604 Joint Australian and New Zealand Standard family for preservative-treated wood-based products, defining hazard classes H1 to H6 and required chemical retentions.
Timber Terminology
- KD (Kiln Dried) Timber dried in a controlled kiln to a target moisture content, typically 10 to 15 percent, producing dimensionally stable boards suited to interior or fine work.
- DAR (Dressed All Round) Timber that has been planed smooth on all four faces to consistent finished dimensions, typically 5 mm smaller than the nominal sawn size.
- DPR (Dressed Pencil Round) Timber dressed all round and finished with small radius edges, presenting a softened arris that resists splintering and improves appearance on exposed members.
- E4E (Eased Four Edges) Timber finished with a small chamfer or rounding on all four longitudinal edges, easing the arrises to reduce splintering and soften appearance.
- F/J (Finger Jointed) Timber assembled from short pieces glued end-to-end with interlocking finger profiles, producing long, stable lengths with reduced bow and twist.
- Hardwood Durability Classes Four-class system rating untreated hardwood heartwood resistance to decay, from Class 1 (highly durable) to Class 4 (least durable) under AS 5604.
Plywood Terminology
- A-Bond Glue Phenol-formaldehyde adhesive bond classified Type A under AS/NZS 2754.1, providing weather, boil, and structural durability for permanent exposure.
- Structural Plywood Engineered plywood manufactured to AS/NZS 2269 with Type A bond and an assigned stress grade, used for flooring, bracing, and structural diaphragms.
- Marine Plywood Premium plywood made to AS/NZS 2272 with Type A bond and high-grade veneers from approved species, designed for boatbuilding and severe wet exposure.
- Exterior Plywood Plywood manufactured to AS/NZS 2271 with Type A bond for non-structural external applications such as soffits, signage, and decorative cladding.
- Form Ply (Formwork Plywood) Structural plywood with a phenolic-film face coating, used for concrete formwork to deliver a smooth off-form finish across multiple pours.
Decking
- R10 Slip Rating Slip-resistance classification under DIN 51130 for surfaces with low slope-angle slip risk, suitable for sheltered residential decks and patios.
- R11 Slip Rating Slip-resistance classification under DIN 51130 for surfaces with moderate slip risk, suitable for exposed decks, balconies, and ramps in residential settings.
- Decking Joist Spans Maximum allowable spacing between deck joists, derived from the decking-board thickness, board span tables, and the decking material's structural properties.
Cladding
- Scyon James Hardie's range of advanced cement-composite cladding, lining, and trim products engineered for greater impact resistance and dimensional stability than standard fibre cement.
- HardieFlex James Hardie's flat fibre-cement sheet, used for eaves, soffits, internal linings, and as a non-combustible substrate for cladding and ceilings.
- Cavity Batten Vertical timber or proprietary batten fixed over wall sarking to create a drained, ventilated cavity behind external cladding, improving moisture management and durability.
- Weatherboard Horizontally fixed external cladding board, traditionally timber but now also fibre-cement or composite, that overlaps the board below to shed water from the wall.
- Sarking / Reflective Wrap Pliable building membrane fixed to the external face of wall or roof framing to manage moisture, air leakage, and (where foil-faced) radiant heat.
Procurement
- Indigenous Procurement Policy (IPP) Australian Government policy requiring Commonwealth agencies to direct a portion of procurement spend to Indigenous-owned businesses, set against published value and volume targets.
- Supply Nation Australia's leading directory and verifier of Indigenous-owned businesses, providing the registration that underpins eligibility for Indigenous Procurement Policy contracts.
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