Species data
Douglas-Fir
Pseudotsuga menziesii - a softwood . Also sold as doug fir, oregon pine, coast douglas-fir.
Properties at a glance
| Janka hardness | 620 lbf |
| Stiffness (MOE) | 1,765,000 psi |
| Specific gravity | 0.51 |
| Density | 31.8 lb/ft3 (510 kg/m3) |
| Weight per board foot | 2.65 lb |
| Shrinkage, green to oven-dry | 7.3% tangential / 4.5% radial |
| Movement coefficient (CT / CR) | 0.00267 / 0.00165 |
| Indicative price | $4.00 per board foot (estimated) |
Values are at about 12% moisture content. Density is specific gravity times 62.4; a board foot is one twelfth of a cubic foot, so weight per board foot is that density divided by twelve. Anything marked estimated is our own figure, not a measured one.
How Douglas-Fir compares
Measured against the 113 solid woods in this database: it is harder than 28% of them, heavier than 27%, and stiffer than 65%.
What that means in the shop
A 4/4 board 8 inches wide and 8 feet long is 5.33 board feet, so in Douglas-Fir it weighs about 14.1 lb. A stack of ten is 141 lb - worth knowing before you load a rack or a car.
Against red oak, the trade's usual yardstick at 1,220 lbf, Douglas-Fir is about 51% as hard and 73% as heavy.
Its shrinkage is 7.3% tangential against 4.5% radial, a ratio of 1.6 to 1. The wider that ratio, the more unevenly a flatsawn board moves across its width as humidity changes, and the more it wants to cup; anything near or above 2 to 1 is worth quartersawing or restraining for panels and wide tops. This one moves comparatively evenly.
Woods of similar hardness
Closest to Douglas-Fir on hardness in this database: Sassafras (630 lbf), Spanish Cedar (600 lbf), Port Orford Cedar (590 lbf), Red Alder (590 lbf). Similar hardness does not mean similar behaviour - check density and movement before substituting one for another.
Related calculators
Sources
- The Wood Database - Douglas-Fir
- Dimensional change coefficient table (Hoadley / FPL Wood Handbook), reproduced by Popular Woodworking
MOE (1,765,000 lbf/in2, averaged across four regions), Janka (620 lbf) and shrinkage (T 7.3%, R 4.5%) from The Wood Database, which cites the USDA FPL Wood Handbook. Specific gravity 0.51 is the Wood Database value at 12% MC for Coast Douglas-fir (it also lists basic 0.45; the FPL Wood Handbook gives 0.48). CT 0.00267 and CR 0.00165 (Douglas-fir, coast) from the Hoadley / FPL dimensional change coefficient table reproduced by Popular Woodworking. Price indicative.
These calculators are for planning and estimation. Engineering results (shelf sag, wood movement) use published average material properties; real boards vary by grade, grain, moisture and defects. Verify load-bearing designs with a professional.