Douglas Fir
Douglas Fir is a strong, stiff structural softwood (EN 13556 PSMe, graded to ASTM D2555 species values) with density about 0.48 g/cm³, tensile strength near 105 MPa, a 13.4 GPa elastic modulus and roughly 1 % elongation.
Reference datasheet — Douglas Fir 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 KD12 condition
Douglas Fir tempers and conditions
Douglas Fir is supplied in 4 conditions, soft to hard. KD12 is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Douglas-fir laminated veneer lumber | Engineered veneer laminate for beams and headers: knots dispersed, so stiffness and strength are higher and far less variable than sawn lumber. | 55 | 0.13 W/m·K | |||
Unseasoned, MC above fibre saturation | Freshly sawn/wet-use lumber: heaviest, softest and lowest strength — use only where drying shrinkage is designed for. | 75 | 0.2 W/m·K | |||
KD19 / S-DRY | Standard framing/dimension-lumber condition sold as S-DRY or KD-HT; the basis for most building-code design values. | 90 | 0.8 | 0.13 W/m·K | ||
KD12Default Kiln-dried to 12 % MC | Reference 12 % moisture condition used for published clear-wood properties and for interior joinery, flooring and millwork. | 105 | 1 | 0.12 W/m·K |
What is Douglas Fir?
Douglas Fir is a strong, stiff structural softwood (EN 13556 PSMe, graded to ASTM D2555 species values) with density about 0.48 g/cm³, tensile strength near 105 MPa, a 13.4 GPa elastic modulus and roughly 1 % elongation. It offers among the best stiffness-to-weight of the common North American framing species and is supplied green, kiln-dried to 19 % or 12 % MC, and as engineered forms such as LVL, glulam and plywood veneer. Practical limits are a 65 °C service ceiling, resin pitch that loads tooling, poor steam-bending and heartwood that resists preservative penetration. Southern Yellow Pine is the alternative where treated stock is required. Douglas Fir has a density of 0.48 g/cm³ (0.0173 lb/in³), lighter than 76% of natural material grades. Douglas Fir has a tensile strength of 105 MPa (15.2 ksi), stronger than 91% of natural material grades. Elongation at break is 1% and the elastic modulus is 13.4 GPa (1.94 Msi).
What is Douglas Fir used for?
- Structural framing
- Glulam beams
- Plywood face veneer
- Marine spars
- Heavy timber construction
Advantages
- Lightweight — 0.48 g/cm³ (0.0173 lb/in³), better than 76% of natural material grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 88% of natural material grades
- Low fracture toughness — 0.4 MPa·√m (0.364 ksi·√in), worse than 86% of natural material grades
Douglas Fir properties
Typical room-temperature values for Douglas Fir-KD12; bars are the position among natural material grades.
Physical2
Douglas Fir has a density of 0.48 g/cm³ (0.0173 lb/in³), lighter than 76% of natural material grades.
Mechanical10
Douglas Fir has a tensile strength of 105 MPa (15.2 ksi), stronger than 91% of natural material grades. Elongation at break is 1% and the elastic modulus is 13.4 GPa (1.94 Msi).
Thermal5
Douglas Fir is rated for continuous service to 65°C (149 °F). It conducts heat at 0.12 W/m·K (0.0693 BTU/hr·ft·°F), worse than 70% of natural material grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
Douglas Fir is an electrical insulator with a dielectric strength of 5 kV/mm (127 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is fair (50/100), better than 63% of natural material grades.
Sustainability4
Producing a kilogram of Douglas Fir takes about 10 MJ of energy and emits 0.35 kg of CO₂ — less than 56% of natural material grades. Typical recycled content is 5%.
Manufacturability2
Douglas Fir's machinability is very good (80/100, worse than 52% 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 Douglas Fir
Is Douglas Fir easy to machine?
Saws, planes and routs easily with carbide tooling; hard latewood bands and resin cause tear-out and pitch build-up, so use sharp tools, high rake and periodic blade cleaning.
Can Douglas Fir be welded?
Not weldable — joined by nails, screws, split-ring/plate connectors, or PVA/PUR/resorcinol and phenolic adhesives (good bonding, but degrease resin-rich surfaces).
Can Douglas Fir be formed, bent or molded?
Poor steam-bending species (low bend ratio); shape by lamination of thin veneers/laminae as in glulam and LVL, allowing 3–5 % tangential shrinkage on drying.
Douglas Fir 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 |
|---|---|---|
| celluloseoven-dry wood basis | 44 – 50 | 47 |
| hemicellulosemainly galactoglucomannan | 18 – 25 | 22 |
| ligninguaiacyl-type softwood lignin | 26 – 31 | 28 |
| extractives (resins, terpenes, phenolicshigher in heartwood; causes resin pockets | 2 – 6 | 3.5 |
| ash (inorganics) | 0.2 – 0.6 | 0.3 |
What surface finishes work on Douglas Fir?
Sands well but raises grain and takes stain unevenly due to strong earlywood/latewood contrast — use conditioner or pigmented primer; heartwood resists preservative pressure treatment and usually needs incising.
Equivalent designations
Standards and trade names that resolve to Douglas Fir in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Pseudotsuga menziesii
How much does Douglas Fir cost?
Douglas Fir is a budget-cost natural material ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Douglas Fir — frequently asked
What is Douglas Fir used for?
Douglas Fir is typically used for structural framing, glulam beams, plywood face veneer, marine spars and heavy timber construction. In short: stiffest common framing softwood; base species for glulam and LVL; poor steam-bending species.
What is the tensile strength of Douglas Fir?
Douglas Fir has a typical tensile strength of 105 MPa (15.2 ksi) — stronger than 91% of natural material grades. Strength varies by condition: see the 4 listed tempers.
Is Douglas Fir easy to machine?
Yes — machinability is rated very good (80/100, worse than 52% of natural material grades). Saws, planes and routs easily with carbide tooling; hard latewood bands and resin cause tear-out and pitch build-up, so use sharp tools, high rake and periodic blade cleaning.
Can Douglas Fir be welded?
Not weldable — joined by nails, screws, split-ring/plate connectors, or PVA/PUR/resorcinol and phenolic adhesives (good bonding, but degrease resin-rich surfaces).
What surface finishes work on Douglas Fir?
Sands well but raises grain and takes stain unevenly due to strong earlywood/latewood contrast — use conditioner or pigmented primer; heartwood resists preservative pressure treatment and usually needs incising.
Can Douglas Fir be formed, bent or molded?
Poor steam-bending species (low bend ratio); shape by lamination of thin veneers/laminae as in glulam and LVL, allowing 3–5 % tangential shrinkage on drying.
What is the maximum service temperature of Douglas Fir?
Douglas Fir is rated for continuous use to about 65°C (149 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Douglas Fir cost?
Douglas Fir is a budget-cost natural material ($), cheaper than about 90% 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-190) — USDA Forest Products Laboratory (2010)
- ASTM D2555 — Establishing Clear Wood Strength Values — ASTM International (2017)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM International (2022)
- EN 13556 — Nomenclature of timbers used in Europe (code PSMe) — CEN (2003)
- LVL Product Guide / Design Properties — APA – The Engineered Wood Association (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; 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.