Red Spruce
Picea rubens · softwood · Northeastern North America · moderate movement
- Janka hardness 490 lbfred oak ≈ 1,290 lbf
- Density ≈ 28 lb/ft³specific gravity 0.4 at 12% MC
- Shrinkage — tangential 7.8%flatsawn width, green → ovendry
- Shrinkage — radial 3.8%quartersawn width
- T/R ratio 2.1 : 1higher = more cupping in flatsawn stock
Shop notes The "Adirondack spruce" of pre-war guitar tops. Straight, stiff, even — treat clear pieces as tonewood, the rest as good framing.
Seasonal movement at a glance
Width change for red spruce 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″ (0.100″) | 1/16″ (0.049″) |
| 12″ | 3/16″ (0.201″) | 3/32″ (0.098″) |
| 24″ | 13/32″ (0.401″) | 3/16″ (0.195″) |
| 36″ | 19/32″ (0.602″) | 9/32″ (0.293″) |
Run your own numbers
Different width, different climate swing — the calculator below is preset to red spruce:
Typical swings:
Red Spruce questions
How much does red spruce move with the seasons?
A 12″-wide flatsawn red spruce board moves about 3/16″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 3/32″. Its tangential shrinkage is 7.8% and radial 3.8% (green to ovendry) — a moderate-movement wood.
How hard is red spruce?
Red Spruce 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 28 lb/ft³ at indoor moisture levels.
Is red spruce good for wide panels and tabletops?
Carefully. Its tangential-to-radial ratio of 2.1:1 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
Grand Fir · 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.