Grand Fir
Abies grandis · softwood · Pacific Northwest · moderate movement
- Janka hardness 490 lbfred oak ≈ 1,290 lbf
- Density ≈ 26 lb/ft³specific gravity 0.37 at 12% MC
- Shrinkage — tangential 7.5%flatsawn width, green → ovendry
- Shrinkage — radial 3.4%quartersawn width
- T/R ratio 2.2 : 1higher = more cupping in flatsawn stock
Shop notes A Hem-Fir-mix species: light, straight, unremarkable — which is exactly what paint-grade work wants.
Seasonal movement at a glance
Width change for grand fir across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:
| Board width | Flatsawn | Quartersawn |
|---|---|---|
| 6″ | 3/32″ (0.096″) | 1/32″ (0.044″) |
| 12″ | 3/16″ (0.193″) | 3/32″ (0.087″) |
| 24″ | 3/8″ (0.386″) | 3/16″ (0.175″) |
| 36″ | 19/32″ (0.579″) | 1/4″ (0.262″) |
Run your own numbers
Different width, different climate swing — the calculator below is preset to grand fir:
Typical swings:
Grand Fir questions
How much does grand fir move with the seasons?
A 12″-wide flatsawn grand fir board moves about 3/16″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 3/32″. Its tangential shrinkage is 7.5% and radial 3.4% (green to ovendry) — a moderate-movement wood.
How hard is grand fir?
Grand Fir rates about 490 lbf on the Janka scale — soft enough to dent in daily use (red oak is roughly 1,290 lbf). Density runs about 26 lb/ft³ at indoor moisture levels.
Is grand fir good for wide panels and tabletops?
Carefully. Its tangential-to-radial ratio of 2.2:1 makes flatsawn boards prone to cupping — choose quartersawn stock for wide glue-ups, alternate growth rings, and fasten tops so they can slide.
Similar species
Red Spruce · White Fir · Eastern Hemlock · Lodgepole Pine · Redwood · White Spruce
Shrinkage, specific gravity, and hardness from the Wood Handbook, FPL-GTR-282 (2021 edition), USDA Forest Products Laboratory (public domain). Values are species averages — individual boards vary with growth conditions and how they were dried.