Redwood OG-KD
Grade · default condition
OG-KD = old-growth heartwood, kiln-dried to ~12% MC
Dense, extractive-rich heartwood (Clear All Heart / Heart B): pick for maximum durability and strength in exposed exterior work.
Values for the OG-KD condition
Other Redwood tempers and conditions
Redwood is listed in 3 conditions; see the grade overview at Redwood.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Green / unseasoned | As-sawn wet stock for cost-driven rough framing or tanks; strength and stiffness are markedly lower and shrinkage/checking must be allowed for. | — | 55 | — | — | 0.18 W/m·K |
Young (second) growth, kiln-dried to ~12% MC | Today's commercial supply: lighter, wider-ringed, less extractive — fine for decking and fencing but noticeably weaker and less durable. | — | 58 | — | — | 0.1 W/m·K |
OG-KDDefaultThis page Old-growth heartwood, kiln-dried to ~12% MC | Dense, extractive-rich heartwood (Clear All Heart / Heart B): pick for maximum durability and strength in exposed exterior work. | — | 70 | 1 | — | 0.11 W/m·K |
What is Redwood OG-KD?
Redwood OG-KD is Redwood in the OG-KD grade — dense, extractive-rich heartwood (Clear All Heart / Heart B): pick for maximum durability and strength in exposed exterior work. Redwood OG-KD has a tensile strength of 70 MPa (10.2 ksi), stronger than 67% of natural material grades. Elongation at break is 1% and the elastic modulus is 9.6 GPa (1.39 Msi). Redwood OG-KD has a density of 0.42 g/cm³ (0.0152 lb/in³), lighter than 84% of natural material grades.
Advantages
- Easy to machine — 90/100, better than 86% of natural material grades
- Lightweight — 0.42 g/cm³ (0.0152 lb/in³), better than 84% of natural material grades
- Good corrosion resistance — 80/100, better than 84% of natural material grades
Limitations
- Low fracture toughness — 0.4 MPa·√m (0.364 ksi·√in), worse than 86% of natural material grades
- Limited service temperature — 70°C (158 °F), worse than 80% of natural material grades
- Poor heat conductor — 0.11 W/m·K (0.0636 BTU/hr·ft·°F), worse than 80% of natural material grades
Redwood OG-KD properties
Typical room-temperature values for Redwood OG-KD; 11 are specific to this condition. Other listed values are Redwood reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Redwood OG-KD has a density of 0.42 g/cm³ (0.0152 lb/in³), lighter than 84% of natural material grades.
Mechanical9
Redwood OG-KD has a tensile strength of 70 MPa (10.2 ksi), stronger than 67% of natural material grades. Elongation at break is 1% and the elastic modulus is 9.6 GPa (1.39 Msi).
Thermal5
Redwood OG-KD is rated for continuous service to 70°C (158 °F). It conducts heat at 0.11 W/m·K (0.0636 BTU/hr·ft·°F), worse than 80% of natural material grades. Thermal expansion is 3.5 µm/m·K (1.94 µin/in·°F).
Electrical1
Redwood OG-KD has an electrical 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 Redwood OG-KD takes about 9 MJ of energy and emits 0.45 kg of CO₂ — less than 65% of natural material grades. Typical recycled content is 8%.
Manufacturability2
Redwood OG-KD'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 Redwood OG-KD
Is Redwood easy to machine?
Cuts, planes and routs very easily with low power and tool wear, but soft earlywood tears — use sharp, high-rake carbide and light finishing cuts.
Can Redwood be welded?
Not weldable; joined mechanically or with PVA/polyurethane/epoxy adhesives — extractives can slightly retard cure, so wipe fresh surfaces with acetone before gluing.
Can Redwood be formed, bent or molded?
Not steam-bendable to any useful radius; shape by sawing, moulding or laminating thin resawn strips.
What surface finishes work on Redwood?
Sands well and accepts oil, semi-transparent stain and water-repellent finishes; water-soluble extractives bleed through latex paint, so seal with a stain-blocking primer and use only stainless or hot-dip galvanized fasteners to avoid black tannin stains.
Redwood 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 |
|---|---|---|
| cellulosestructural microfibrils | 42 – 48 | 45 |
| hemicellulose | 18 – 25 | 22 |
| ligninguaiacyl-type softwood lignin | 27 – 34 | 30 |
| extractives (polyphenols/tannins)heartwood only; source of natural decay resistance | 2 – 15 | 6 |
| ash | 0.1 – 0.5 | 0.3 |
Redwood OG-KD — frequently asked
What is Redwood OG-KD used for?
Redwood OG-KD is typically used for decking, outdoor furniture, siding, fencing and hot tub staves. In short: naturally decay-resistant softwood; very low shrinkage outdoors; bleeds tannin through paint.
What is the tensile strength of Redwood OG-KD?
Redwood OG-KD has a typical tensile strength of 70 MPa (10.2 ksi) — stronger than 67% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Redwood OG-KD easy to machine?
Yes — machinability is rated excellent (90/100, better than 86% of natural material grades). Cuts, planes and routs very easily with low power and tool wear, but soft earlywood tears — use sharp, high-rake carbide and light finishing cuts.
Can Redwood OG-KD be welded?
Not weldable; joined mechanically or with PVA/polyurethane/epoxy adhesives — extractives can slightly retard cure, so wipe fresh surfaces with acetone before gluing.
What surface finishes work on Redwood OG-KD?
Sands well and accepts oil, semi-transparent stain and water-repellent finishes; water-soluble extractives bleed through latex paint, so seal with a stain-blocking primer and use only stainless or hot-dip galvanized fasteners to avoid black tannin stains.
Can Redwood OG-KD be formed, bent or molded?
Not steam-bendable to any useful radius; shape by sawing, moulding or laminating thin resawn strips.
What is the maximum service temperature of Redwood OG-KD?
Redwood OG-KD is rated for continuous use to about 70°C (158 °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, FPL-GTR-282 — USDA Forest Products Laboratory (2021)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM (2022)
- ASTM D2555 — Establishing Clear Wood Strength Values — ASTM (2017)
- EN 13556 — Round and sawn timber: nomenclature of timbers (code SESE) — CEN (2003)
- Redwood Lumber Grades & Specification Guide — California Redwood Association / Redwood Inspection Service (2019)
- CES EduPack / Granta natural materials records — softwood — Ansys Granta (2023)
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.