Pine framing grades: MGP10, MGP12, MGP15, F-grades, and treatment levels

TL;DR

MGP10, MGP12, and MGP15 are the machine-graded stress grades used for seasoned softwood (radiata pine) framing in most Australian residential jobs. The grade number (10, 12, 15) is a rounded modulus of elasticity in GPa; higher is stiffer and stronger. AS 1684.2:2021 is the deemed-to-satisfy standard under NCC 2022: you look up the span table for your wind classification, stress grade, and member spacing to get the minimum member size (verified 2026-05-08). Wrong grade on site, or a delivery docket that does not confirm grade, is a non-compliant frame. Treatment level (H1 to H4) is a separate question from structural grade: H2 is the standard for dry internal framing in termite-risk areas, H3 for external above-ground members.

What it is

Structural pine framing for Australian residential construction is primarily plantation radiata pine, machine graded and treated before delivery. The two classification systems that appear on a delivery docket are:

Stress grade: the structural rating (MGP10, MGP12, MGP15 for machine-graded pine; F5, F7, F8, F11, F14 for visually graded timber). Determines which span table row to read.
Hazard (treatment) level: the preservative treatment classification (H1 to H4 for typical residential framing applications). Determines whether the timber is appropriate for the exposure condition.

These are independent of each other. A stick of 90x45 might be stamped “MGP10 H2” (stress grade + treatment level). Both must be confirmed before framing begins.

Properties

Standard framing sizes

Nominal size	Common use
70x35 mm	Light non-structural walls, partition studs at close centres
70x45 mm	Partition studs, trimmer studs
90x35 mm	Budget studs, light-duty external walls
90x45 mm	Standard wall studs, top and bottom plates, ceiling joists, noggings
140x45 mm	Lintels, bearers, floor joists for short spans
190x45 mm	Lintels, bearers, floor joists for medium spans
240x45 mm	Larger lintels and beams
290x45 mm	Long-span lintels and beams (verify via span table or engineer)

Source: Common stock sizes confirmed against supplier product listings across multiple Australian building merchants (verified 2026-05-08).

Moisture content

Seasoned pine framing has a moisture content at or below 15% (verified 2026-05-08, per AS 1684.2 guidance and Australian industry standard). Unseasoned or “green” timber is above approximately 25% moisture content and is addressed by separate AS 1684 span table supplements. For residential framing in most states, kiln-dried seasoned timber (10 to 15% MC) is standard and expected on delivery.

Using green or insufficiently dried framing leads to shrinkage, screw pops, joint cracking in linings, and frame distortion as the timber dries in place.

Grades and variants

MGP stress grades (machine-graded pine)

Machine grading measures the stiffness (modulus of elasticity, MOE) of each stick by bending it and recording the deflection response. It is more consistent than visual grading and is the standard method for plantation radiata pine from large Australian mills.

Grade	Characteristic MOE	Approximate F-grade equivalent	Primary use
MGP10	10,000 MPa	F5	General framing: wall studs, plates, noggings, ceiling joists, short-span floor joists
MGP12	12,000 MPa	F8	Longer spans and heavier loads: bearers, lintels, floor joists
MGP15	15,000 MPa	F11	Maximum load / longest spans: primary beams, large lintels

F-grade equivalences sourced from AS 1684.2 span table supplement documentation and the FWPA/WoodSolutions framing guide (verified 2026-05-08).

AS 1684.2:2021 span table supplements are published separately for seasoned softwood at MGP10, MGP12, and MGP15 for wind classifications N1 to N4 (non-cyclonic). A separate set covers cyclonic zones (AS 1684.3). Each supplement contains 53 design tables covering rafters, ceiling joists, floor joists, bearers, lintels, studs, and bracing members (verified 2026-05-08).

F-grade stress grades (visually graded)

Visual grading classifies timber by observable features (knot size, grain slope, checks, shakes). The F-number represents bending strength in MPa. Common F-grades and their span table equivalents:

Grade	Approx. MGP equivalent	Typical application
F5	MGP10	Minimum structural softwood framing
F7	Between MGP10/MGP12	Mid-range softwood framing
F8	MGP12	Common hardwood framing grade
F11	MGP15	Higher-grade hardwood framing
F14, F17, F27	Above MGP15	Structural hardwood; rare in standard residential framing

AS 1684.2 span table supplements cover unseasoned softwood (F5, F7), seasoned softwood (F5, F7, F8, MGP10, MGP12, MGP15), unseasoned hardwood (F8, F11, F14, F17), and seasoned hardwood (F14, F17, F27) (verified 2026-05-08).

Important: MGP vs F-grade are not freely interchangeable

Use the span table supplement for the grade you have on site. The F-grade equivalences above are approximate and hold for most span table inputs, but they are not a licence to substitute grades without checking the relevant table. If the delivery provides MGP10 and you designed to MGP12, re-check your spans.

Hazard (treatment) levels

Treatment is governed by the AS/NZS 1604 series. The H-code describes the biological hazard the timber must resist. For residential framing, the relevant levels are H1 to H4.

Hazard level	Exposure	Typical framing use	Preservative types
H1	Completely protected indoors, no insect risk	Furniture, non-structural internal joinery	Light insecticide
H2	Internal framing in termite-prone areas, protected from weather	Wall studs, top/bottom plates, ceiling joists, roof framing (standard dry internal framing)	Termiticide (no fungicide needed)
H3	Above-ground external, exposed to weather or periodic wetting	External pergola framing, exposed fascia, deck joists and bearers above ground	Fungicide + termiticide (LOSP, ACQ, or CCA)
H4	Ground contact or continual damp conditions	Posts in contact with soil, retaining sleepers, stumps	High-retention preservative (ACQ, CCA)

Sources: AS/NZS 1604.1:2010, preservative treatment specification; WoodSolutions durability guide; industry supplier product specifications (verified 2026-05-08).

H2 “blue pine” or “pink pine”: H2-treated radiata pine is the standard for internal wall and roof framing in termite management zones. The treatment provides insect (termite and borer) protection but no fungal protection, so H2 pine must remain dry. It is NOT suitable for any external or ground-contact application. States with a high termite risk (most of mainland Australia excluding TAS and elevated alpine areas) require H2 or a physical/chemical termite management system under NCC 2022 Housing Provisions Part 5 (verified 2026-05-08).

H3 LOSP treated pine: LOSP (Light Organic Solvent Preservative) H3 timber is commonly used for external deck framing (joists, bearers) and pergolas. LOSP H3 is above-ground only; it is not rated for ground contact. For ground contact, H4 is required.

LOSP vs CCA vs ACQ: LOSP (Light Organic Solvent Preservative) provides insecticide and fungicide in an organic solvent carrier. CCA (Copper Chrome Arsenate) is the most widely available; it contains arsenic and is subject to handling restrictions. ACQ (Alkaline Copper Quaternary) is the arsenic-free alternative (verified 2026-05-08).

Where to use

H2 MGP10 or MGP12: standard internal wall framing, roof framing, and ceiling framing across most Australian residential projects in termite-risk zones
H3 MGP10: external pergola, carport, and deck framing (above ground only); eaves framing where periodic wetting is possible
Untreated MGP10 / MGP12: internal framing where there is no termite risk (check state NCC provisions; untreated pine is permitted in low-risk zones with physical barriers)
MGP15 or F14+: long-span or heavily loaded members where span tables require a higher grade; confirm with engineer on anything outside standard AS 1684 scope (two storeys max, 16 m max building width)

Where NOT to use

H2 treated pine in any external, exposed, or damp location. The treatment provides insect protection but no fungal protection. Wet H2 pine will rot.
H1 treated pine as structural framing. H1 is for furniture and non-structural applications.
Ungraded or “random” pine (without a visible grade stamp or docket confirmation) in any structural application. No grade confirmation, no span table entry is valid.
Unseasoned framing (green, high-MC) in positions where the span table assumes seasoned timber. Green timber will shrink and distort; linings applied over green frame will crack and pop.
Substituting a lower grade because it is on site. If the structural design or span table requires MGP12, ordering MGP10 is not an acceptable substitution.

Fixing and installation

Grade confirmation before framing

Every stick of structural pine should carry a grade stamp or be accompanied by a delivery docket stating the stress grade and hazard level. The stamp typically shows: species or species group, grade (e.g. MGP10), treatment level (e.g. H2), and moisture content category (seasoned) (verified 2026-05-08, WoodSolutions framing guide). If grade cannot be confirmed from the docket, do not use the timber for structural framing.

Common framing spacings

Member	Typical spacing (non-cyclonic, standard loading)
Wall studs	450 mm or 600 mm centres (confirm via AS 1684 span table for the specific stud size, grade, and load)
Ceiling joists	450 mm or 600 mm centres
Floor joists	450 mm or 600 mm centres (beams may be wider if span table permits)
Roof rafters	600 mm or 900 mm centres (check table)

Spacings listed are indicative starting points only. Actual required spacing depends on span, load width, timber size, stress grade, and wind classification. Always confirm via the relevant AS 1684.2 span table supplement (verified 2026-05-08).

AS 1684 span table inputs (four required)

Using a span table requires four correct inputs. A wrong input in any one produces a non-compliant member:

Wind classification for the site (N1–N4, or C1–C3 for cyclonic): from the local council or wind engineer, or calculated per AS 4055
Stress grade and timber type confirmed from the delivery docket (e.g. Seasoned Softwood MGP10)
Member spacing (stud, joist, rafter centres in mm)
Load width (the tributary floor or roof area the member carries, in metres)

Using a span table supplement from a superseded edition of AS 1684 (e.g. the 2006 or 2010 edition) on a new build is a common compliance error. AS 1684.2:2021 (with Amendment 1:2024) is the current edition. The 2024 amendment updated bracing and tie-down capacities but did not change the member span tables (verified 2026-05-08).

NCC 2022 compliance pathway

AS 1684.2:2021 is a deemed-to-satisfy (DTS) solution under NCC 2022 Volume Two / ABCB Housing Provisions for structural framing in Class 1 and Class 10 buildings in non-cyclonic areas, subject to scope limits: maximum two storeys of timber framing, maximum building width 16,000 mm (excluding eaves), maximum wall height 3,000 mm (verified 2026-05-08). Outside those limits, refer to AS 1720.1 (structural timber design) and engage an engineer.

Tolerances and acceptance

Numerical

Item	Limit	Source
Frame straightness: individual stud bow (in plane)	Per current HIA Guide to Materials and Workmanship. Verified numerical value pending HIA member access. [HIA-056]	HIA Guide / state guide
Frame straightness: top plate line under straightedge	Per current HIA Guide to Materials and Workmanship. Verified numerical value pending HIA member access. [HIA-057]	HIA Guide / state guide
Stud plumb (deviation from vertical)	Per current HIA Guide to Materials and Workmanship. Verified numerical value pending HIA member access. [HIA-058]	HIA Guide / state guide

Visual acceptance

Grade stamp or confirmed delivery docket present for all structural members
Treatment level correct for the exposure (H2 internal, H3 external above-ground, H4 ground contact)
Moisture content confirmed as seasoned (if the relevant span table supplement is for seasoned timber)
No members with excessive splits, large knots, or visible warp beyond what the grading machine already accounted for in the grade
Notching and drilling for services within the limits specified in AS 1684.2 Section 7 (do not over-notch)

Defects typical at PCI

Screw pops and joint cracks in linings: green or high-MC framing installed and timber dried in situ
Stud bow telegraphing through plasterboard as shadow/waviness in raking light
Incorrect grade on site (untreated or wrong H-level): commonly found when builder did not verify docket, especially where “treated pine” was ordered without specifying the H level
Notching or drilling in prohibited zones weakening framing members

Working with other trades

Chippy (framing carpenter): responsible for confirming grade and treatment on delivery, building the frame to AS 1684.2, and ensuring member sizes match the span tables for the wind classification
Builder / site manager: responsible for ordering the correct grade (MGP10 or MGP12) and hazard level (H2 for internal, H3 for external) and confirming delivery dockets before framing commences
Building certifier / inspector: will check the delivery docket or grade stamp if queried; non-compliant framing is a stop-work issue
Plasterer / lining installer: check frame moisture content and straightness before lining; boarding over a bowed or wet frame guarantees lining defects

Health and safety

Manual handling: structural pine framing sticks are heavy and awkward; 90x45 at 6 m is approximately 10 to 12 kg, longer beams considerably more. Two-person lift or mechanical assist for large members.
Silica and dust: sawdust from structural pine is a nuisance dust. P1 mask for general cutting. Treated pine (H2, H3) generates dust that may contain preservative residue; P2 mask, eye protection, and avoid burning offcuts (burning CCA-treated timber releases arsenic compounds).
CCA offcuts: treated timber offcuts classified as hazardous waste in most states. Do not burn. Dispose per state EPA guidelines.
Termiticide-treated timber (H2): avoid prolonged skin contact with freshly treated stocks, especially if the treatment is wet or the timber is freshly treated. Standard builders’ gloves and washing before eating or smoking.

Suppliers

Multinail / Carter Holt Harvey Woodproducts (Hyspan, Truform): major mill and brand in the Australian structural pine market
Hyne Timber: Queensland and national, wide range of MGP and treatment grades
Boral Timber (historical brand, now through various distributors)
Pine treated suppliers by region: most building merchants stock 90x45 MGP10 H2 as a commodity item. MGP12 and MGP15 are less universally stocked; order in advance for larger sizes (190x45 and above).

Trade pickup: Bowens, Blacktown Timber, Mitre 10 Trade, Bunnings Trade, regional timber yards.

[Sponsor / preferred supplier slot. ACCC disclosure required.]

What can go wrong

Wrong grade delivered: supplier substitutes MGP10 where MGP12 was specified. Common where orders are loose. Always check the docket before framing.
Untreated in a termite zone: internal framing goes in without H2 treatment in a high-termite-risk zone. This is a building defect and a NCC non-compliance.
H2 used externally: pergola or carport framing specified as H2 instead of H3. H2 has no fungal protection; it will rot when wet.
Green framing: high-MC timber installed, linings applied, timber shrinks in situ, screw pops and joint cracks appear at the 3-to-6-month mark.
Wrong span table edition: old AS 1684.2-2006 span tables used on a new build; structural certification cannot confirm compliance with NCC 2022.
Over-notched or over-drilled members: plumbers and sparkies drilling too large or too close to the edge of a framing member. AS 1684.2 Section 7 specifies limits. Common in tight ceiling joist zones.
No grade confirmation: framing proceeds without checking dockets. Certifier cannot sign off; framing must be sampled or replaced.

References

AS 1684.2:2021 Amd 1:2024, Residential timber-framed construction, Part 2: Non-cyclonic areas (Standards Australia) (verified 2026-05-08)
AS 1684.3:2010, Residential timber-framed construction, Part 3: Cyclonic areas (Standards Australia) (verified 2026-05-08)
AS/NZS 1748.1:2011, Timber: Solid: Stress-graded for structural purposes, General requirements (Standards Australia) (verified 2026-05-08)
AS/NZS 1604.1:2010, Specification for preservative treatment, Part 1: Sawn and round timber (Standards Australia) (verified 2026-05-08)
NCC 2022 Volume Two and ABCB Housing Provisions, Class 1 and 10 structural framing requirements (ABCB) (verified 2026-05-08)
WoodSolutions, Lightweight Timber Framing Guide (Forest and Wood Products Australia, woodsolutions.com.au) (verified 2026-05-08)
HIA Guide to Materials and Workmanship (national, Housing Industry Association) (tolerance values pending HIA member access)