OSB/3
Grade · default condition
ASTM D5456 / EN 300 · GB GB/T 22349
OSB/3 = load-bearing panel, humid conditions
The mainstream construction grade: structural sheathing for walls, roofs and floors in service class 2 (humid, protected from weathering).
Values for the OSB/3 condition
Other OSB tempers and conditions
OSB is listed in 4 conditions; see the grade overview at OSB.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
General purpose / interior fitments, dry conditions | Cheapest non-structural grade for furniture backs, interior fitments and packaging in dry (service class 1) use only. | — | 9 | 0.8 | — | 0.12 W/m·K |
Load-bearing panel, dry conditions | Structural grade for interior load-bearing use where the panel stays dry (service class 1); usually MUF/PF bonded. | — | 11 | 0.9 | — | 0.13 W/m·K |
OSB/3DefaultThis page Load-bearing panel, humid conditions | The mainstream construction grade: structural sheathing for walls, roofs and floors in service class 2 (humid, protected from weathering). | — | 12 | 1 | — | 0.13 W/m·K |
Heavy-duty load-bearing panel, humid conditions | Higher-density, higher-resin grade for long spans, I-joist webs and heavy point loads in humid service. | — | 16 | — | — | 0.14 W/m·K |
What is OSB/3?
OSB/3 is OSB in the OSB/3 grade — the mainstream construction grade: structural sheathing for walls, roofs and floors in service class 2 (humid, protected from weathering). OSB/3 has a tensile strength of 12 MPa (1.74 ksi), weaker than 68% of natural material grades. Elongation at break is 1% and the elastic modulus is 3.5 GPa (0.508 Msi). OSB/3 has a density of 0.64 g/cm³ (0.0231 lb/in³), lighter than 60% of natural material grades.
Advantages
- Tough — resists crack growth — 0.65 MPa·√m (0.592 ksi·√in), better than 75% of natural material grades
Limitations
- Limited service temperature — 60°C (140 °F), worse than 94% of natural material grades
- Hard to polish — 12/100, worse than 94% of natural material grades
- Needs corrosion protection — 30/100, worse than 77% of natural material grades
OSB/3 properties
Typical room-temperature values for OSB/3; 13 are specific to this condition. Other listed values are OSB reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
OSB/3 has a density of 0.64 g/cm³ (0.0231 lb/in³), lighter than 60% of natural material grades.
Mechanical9
OSB/3 has a tensile strength of 12 MPa (1.74 ksi), weaker than 68% of natural material grades. Elongation at break is 1% and the elastic modulus is 3.5 GPa (0.508 Msi).
Thermal5
OSB/3 is rated for continuous service to 60°C (140 °F). It conducts heat at 0.13 W/m·K (0.0751 BTU/hr·ft·°F), worse than 57% of natural material grades. Thermal expansion is 7 µm/m·K (3.89 µin/in·°F).
Electrical1
OSB/3 has an electrical resistivity of 1×10⁸ Ω·m.
Chemical & Environmental1
Corrosion resistance is poor (30/100), worse than 77% of natural material grades.
Sustainability4
Producing a kilogram of OSB/3 takes about 15 MJ of energy and emits 0.45 kg of CO₂ — more than 77% of natural material grades. Typical recycled content is 5%.
Manufacturability2
OSB/3's machinability is excellent (85/100, better than 63% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with OSB/3
Is OSB easy to machine?
Cuts and routs easily with carbide-tipped saws and spiral bits, but resin and grit are abrasive — expect short tool life and heavy dust extraction; score cuts to limit edge chip-out.
Can OSB be welded?
Not weldable; join by nails/staples/screws (edge distance ≥ 8 mm), construction adhesive or PVA/PU glue on faces.
Can OSB be formed, bent or molded?
Supplied as flat rigid panel; only mild cold curving over large radii, no thermoforming — panels are hot-pressed at the mill.
What surface finishes work on OSB?
Sand and seal or prime heavily before painting (strand texture and resin telegraph through); edges need sealing against moisture swell, or use factory-coated/T&G panels.
OSB chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| PMDI / PF / MUF resin binderPMDI or PF in core/face for OSB/3–4; MUF typical for OSB/2 | 2.5 – 7 | 4.5 |
| paraffin wax emulsionwater-repellent sizing | 0.5 – 1.5 | 1 |
| moistureequilibrium MC at 20 °C / 65 % RH | 2 – 9 | 6 |
| wood strands (softwood: pine/poplar/eucaoriented, ~75–150 mm long strands, cross-layered | ≥ 90 (balance) | — |
OSB/3 — frequently asked
What is OSB/3 used for?
OSB/3 is typically used for wall/roof/floor sheathing, I-joist webs, packaging, furniture substrate and formwork. In short: lowest-cost structural sheathing; plywood-like shear capacity; abrasive on cutting tools.
What is the tensile strength of OSB/3?
OSB/3 has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 68% of natural material grades. Strength varies by condition: see the 4 listed tempers.
Is OSB/3 easy to machine?
Yes — machinability is rated excellent (85/100, better than 63% of natural material grades). Cuts and routs easily with carbide-tipped saws and spiral bits, but resin and grit are abrasive — expect short tool life and heavy dust extraction; score cuts to limit edge chip-out.
Can OSB/3 be welded?
Not weldable; join by nails/staples/screws (edge distance ≥ 8 mm), construction adhesive or PVA/PU glue on faces.
What surface finishes work on OSB/3?
Sand and seal or prime heavily before painting (strand texture and resin telegraph through); edges need sealing against moisture swell, or use factory-coated/T&G panels.
Can OSB/3 be formed, bent or molded?
Supplied as flat rigid panel; only mild cold curving over large radii, no thermoforming — panels are hot-pressed at the mill.
What is the maximum service temperature of OSB/3?
OSB/3 is rated for continuous use to about 60°C (140 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 300 — Oriented Strand Boards (OSB): definitions, classification and specifications — CEN (2006)
- EN 12369-1 — Characteristic values for wood-based panels: OSB, particleboards and fibreboards — CEN (2001)
- ASTM D2718 — Standard Test Methods for Structural Panels in Planar Shear (Rolling Shear) — ASTM (2018)
- Wood Handbook — Wood as an Engineering Material (Ch. 11, Wood-Based Composite Materials) — USDA Forest Products Laboratory (2021)
- Panel Design Specification / OSB Performance Guide — APA – The Engineered Wood Association (2019)
- ISO 10456 / EN 12524 thermal design values for wood-based panels — ISO (2007)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.