Cedar GRN (Green)
Finish state
Take freshly sawn wet stock for heavy members that will dry on site or for blanks to be preservative-treated; strength and stiffness are clearly lower and thermal conductivity higher.
Values for the GRN condition
Other Cedar tempers and conditions
Cedar is listed in 3 conditions; see the grade overview at Cedar.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
GRNThis page Green | Take freshly sawn wet stock for heavy members that will dry on site or for blanks to be preservative-treated; strength and stiffness are clearly lower and thermal conductivity higher. | — | 45 | 1.3 | — | 0.14 W/m·K |
KD12Default Kiln-dried, 12 % moisture content | Use the standard kiln-dried engineering and construction state at about 12 % moisture content, the condition to which the published handbook mechanical values apply. | — | 55 | 1 | — | 0.09 W/m·K |
Oven-dry | Use the oven-dry, 0 % moisture reference state for laboratory baselines or dry indoor work such as models, instruments and sauna lining: highest strength but brittle and it swells on re-absorption. | — | 62 | 0.8 | — | 0.08 W/m·K |
What is Cedar GRN?
Cedar GRN is Cedar supplied in the GRN condition — take freshly sawn wet stock for heavy members that will dry on site or for blanks to be preservative-treated; strength and stiffness are clearly lower and thermal conductivity higher. Cedar GRN has a tensile strength of 45 MPa (6.53 ksi), stronger than 64% of natural material grades. Elongation at break is 1.3% and the elastic modulus is 6.5 GPa (0.943 Msi). Cedar GRN has a density of 0.44 g/cm³ (0.0159 lb/in³), lighter than 81% of natural material grades. KD12 is the default condition FabDigit quotes; GRN is available on request or by drawing note.
Advantages
- Lightweight — 0.44 g/cm³ (0.0159 lb/in³), better than 81% of natural material grades
- Good corrosion resistance — 70/100, better than 78% of natural material grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 88% of natural material grades
Cedar GRN properties
Typical room-temperature values for Cedar GRN; 13 are specific to this condition. Other listed values are Cedar reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Cedar GRN has a density of 0.44 g/cm³ (0.0159 lb/in³), lighter than 81% of natural material grades.
Mechanical9
Cedar GRN has a tensile strength of 45 MPa (6.53 ksi), stronger than 64% of natural material grades. Elongation at break is 1.3% and the elastic modulus is 6.5 GPa (0.943 Msi).
Thermal5
Cedar GRN is rated for continuous service to 65°C (149 °F). It conducts heat at 0.14 W/m·K (0.0809 BTU/hr·ft·°F), worse than 51% of natural material grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
Cedar GRN is an electrical insulator with a dielectric strength of 1.5 kV/mm (38.1 V/mil) and a resistivity of 10,000 Ω·m.
Chemical & Environmental1
Corrosion resistance is very good (70/100), better than 78% of natural material grades.
Sustainability4
Producing a kilogram of Cedar GRN takes about 9 MJ of energy and emits 0.45 kg of CO₂ — less than 71% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Cedar GRN's machinability is very good (80/100, worse than 52% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Cedar GRN
Is Cedar easy to machine?
Very easy to saw, mill and plane, but the wood is soft, so sharp tooling and high spindle speed are needed to avoid fuzzy surfaces and crushed edges. The earlywood/latewood hardness difference causes sanding ripple; back abrasives with a hard block.
Can Cedar be welded?
Not applicable. Bond with PVA, polyurethane or epoxy, or fasten with stainless screws or pneumatic nails, pre-drilling near edges and ends to prevent splitting.
Can Cedar be formed, bent or molded?
Steam-bending performance is poor and stock breaks readily; use laminated bends or design straight-grained members. Shrinkage is low, about 2.4 % radial and 5 % tangential.
What surface finishes work on Cedar?
Paints and stains well, but heartwood extractives bleed and require a stain-blocking sealer primer. Fasteners must be stainless steel or hot-dip galvanized — plain carbon steel and aluminium corrode against the acidic extractives and leave black staining.
Cedar 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 |
|---|---|---|
| cellulosecrystalline and amorphous cellulose | 40 – 48 | 45 |
| hemicellulosemainly galactoglucomannan | 18 – 26 | 22 |
| ligninguaiacyl lignin | 28 – 34 | 31 |
| extractivesheartwood extractives: thujaplicins, thujic acid; antimicrobial | 2 – 10 | 5 |
| ash | 0.2 – 0.5 | 0.3 |
Cedar GRN — frequently asked
What is Cedar GRN used for?
Cedar GRN is typically used for siding & shingles, outdoor furniture, closet lining, fencing and boat building. In short: lightest decay-resistant softwood; best untreated rot resistance; soft, low-strength surface.
What is the tensile strength of Cedar GRN?
Cedar GRN has a typical tensile strength of 45 MPa (6.53 ksi) — stronger than 64% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Cedar GRN easy to machine?
Yes — machinability is rated very good (80/100, worse than 52% of natural material grades). Very easy to saw, mill and plane, but the wood is soft, so sharp tooling and high spindle speed are needed to avoid fuzzy surfaces and crushed edges. The earlywood/latewood hardness difference causes sanding ripple; back abrasives with a hard block.
Can Cedar GRN be welded?
Not applicable. Bond with PVA, polyurethane or epoxy, or fasten with stainless screws or pneumatic nails, pre-drilling near edges and ends to prevent splitting.
What surface finishes work on Cedar GRN?
Paints and stains well, but heartwood extractives bleed and require a stain-blocking sealer primer. Fasteners must be stainless steel or hot-dip galvanized — plain carbon steel and aluminium corrode against the acidic extractives and leave black staining.
Can Cedar GRN be formed, bent or molded?
Steam-bending performance is poor and stock breaks readily; use laminated bends or design straight-grained members. Shrinkage is low, about 2.4 % radial and 5 % tangential.
What is the maximum service temperature of Cedar GRN?
Cedar GRN is rated for continuous use to about 65°C (149 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Wood Handbook — Wood as an Engineering Material, GTR-190, Ch.5 Mechanical Properties — USDA Forest Products Laboratory (2010)
- EN 13556 — Round and sawn timber, nomenclature of timbers (code THPL) — CEN (2003)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM (2022)
- EN 350 — Durability of wood and wood-based products, natural durability classes — CEN (2016)
- Western Red Cedar Technical Data (thermal, dimensional, fastener guidance) — Western Red Cedar Lumber Association (WRCLA) (2021)
- Inventory of Carbon & Energy (ICE) v3 — sawn softwood — Circular Ecology (2019)
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.