Cedar KD12
Finish state · default condition
KD12 = 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.
Values for the KD12 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 |
|---|---|---|---|---|---|---|
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 |
KD12DefaultThis page 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 KD12?
Cedar KD12 is Cedar supplied in the KD12 condition — use the standard kiln-dried engineering and construction state at about 12 % moisture content, the condition to which the published handbook mechanical values apply. Cedar KD12 has a tensile strength of 55 MPa (7.98 ksi), stronger than 64% of natural material grades. Elongation at break is 1% and the elastic modulus is 7.7 GPa (1.12 Msi). Cedar KD12 has a density of 0.37 g/cm³ (0.0134 lb/in³), lighter than 87% of natural material grades.
Advantages
- Lightweight — 0.37 g/cm³ (0.0134 lb/in³), better than 87% of natural material grades
- Easy to machine — 90/100, better than 86% of natural material grades
- Good corrosion resistance — 80/100, better than 84% of natural material grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 88% of natural material grades
- Poor heat conductor — 0.09 W/m·K (0.052 BTU/hr·ft·°F), worse than 87% of natural material grades
- Low fracture toughness — 0.4 MPa·√m (0.364 ksi·√in), worse than 86% of natural material grades
Cedar KD12 properties
Typical room-temperature values for Cedar KD12; 12 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 KD12 has a density of 0.37 g/cm³ (0.0134 lb/in³), lighter than 87% of natural material grades.
Mechanical9
Cedar KD12 has a tensile strength of 55 MPa (7.98 ksi), stronger than 64% of natural material grades. Elongation at break is 1% and the elastic modulus is 7.7 GPa (1.12 Msi).
Thermal5
Cedar KD12 is rated for continuous service to 65°C (149 °F). It conducts heat at 0.09 W/m·K (0.052 BTU/hr·ft·°F), worse than 87% of natural material grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
Cedar KD12 is an electrical insulator with a dielectric strength of 1.5 kV/mm (38.1 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is very good (80/100), better than 84% of natural material grades.
Sustainability4
Producing a kilogram of Cedar KD12 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 KD12's machinability is excellent (90/100, better than 86% 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 Cedar KD12
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 KD12 — frequently asked
What is Cedar KD12 used for?
Cedar KD12 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 KD12?
Cedar KD12 has a typical tensile strength of 55 MPa (7.98 ksi) — stronger than 64% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Cedar KD12 easy to machine?
Yes — machinability is rated excellent (90/100, better than 86% 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 KD12 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 KD12?
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 KD12 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 KD12?
Cedar KD12 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.