Redwood
Redwood (EN 13556 SESE) is a lightweight, straight-grained softwood at about 0.42 g/cm³, with 70 MPa tensile strength, a 9.6 GPa elastic modulus and heartwood extractives that give natural decay resistance (corrosion score 80).
Reference datasheet — Redwood is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the OG-KD condition
Redwood tempers and conditions
Redwood is supplied in 3 conditions, soft to hard. OG-KD is the default FabDigit quotes; the values on this page are for it.
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-KDDefault 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?
Redwood (EN 13556 SESE) is a lightweight, straight-grained softwood at about 0.42 g/cm³, with 70 MPa tensile strength, a 9.6 GPa elastic modulus and heartwood extractives that give natural decay resistance (corrosion score 80). It machines very easily (score 90) and moves little in service, so it is used for exterior decking, siding and tank work; grades on file are old-growth kiln-dried, young-growth kiln-dried and green. Limits are low strength and stiffness, a 70 °C service ceiling and water-soluble extractives that bleed through paint. Western red cedar is the nearest alternative. Redwood has a density of 0.42 g/cm³ (0.0152 lb/in³), lighter than 84% of natural material grades. Redwood 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).
What is Redwood used for?
- Decking
- Outdoor furniture
- Siding
- Fencing
- Hot tub staves
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 properties
Typical room-temperature values for Redwood-OG-KD; bars are the position among natural material grades.
Physical2
Redwood has a density of 0.42 g/cm³ (0.0152 lb/in³), lighter than 84% of natural material grades.
Mechanical9
Redwood 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 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 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 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's machinability is excellent (90/100, better than 86% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Working with Redwood
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.
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 |
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.
How much does Redwood cost?
Redwood is a standard-cost natural material ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Redwood — frequently asked
What is Redwood used for?
Redwood is typically used for decking, outdoor furniture, siding, fencing and hot tub staves. In short: naturally decay-resistant softwood; very low shrinkage outdoors; bleeds tannin through paint.
What is the tensile strength of Redwood?
Redwood has a typical tensile strength of 70 MPa (10.2 ksi) — stronger than 67% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Redwood easy to machine?
Yes — machinability is rated excellent (90/100, better than 86% of natural material grades). Cuts, planes and routs very easily with low power and tool wear, but soft earlywood tears — use sharp, high-rake carbide and light finishing cuts.
Can Redwood be welded?
Not weldable; joined mechanically or with PVA/polyurethane/epoxy adhesives — extractives can slightly retard cure, so wipe fresh surfaces with acetone before gluing.
What surface finishes work on Redwood?
Sands well and accepts oil, semi-transparent stain and water-repellent finishes; water-soluble extractives bleed through latex paint, so seal with a stain-blocking primer and use only stainless or hot-dip galvanized fasteners to avoid black tannin stains.
Can Redwood be formed, bent or molded?
Not steam-bendable to any useful radius; shape by sawing, moulding or laminating thin resawn strips.
What is the maximum service temperature of Redwood?
Redwood is rated for continuous use to about 70°C (158 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Redwood cost?
Redwood is a standard-cost natural material ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.