All species / Sitka Spruce

Sitka Spruce (Picea sitchensis)

Ladders, boatbuilding, soundboards and light framing; exceptional stiffness for its weight.

The data

Stiffness (modulus of elasticity)1,570,000 psi

Specific gravity (12% MC)0.4

Janka hardness510 lbf

Average dried weight27.0 lb/ft³

Shrinkage, radial (green → dry)4.3%

Shrinkage, tangential7.5%

Shrinkage, volumetric11.5%

Movement classAverage movement

Stiffness & hardness: USDA Wood Handbook (Table 5-3 class data). Shrinkage: USDA Wood Handbook. Full sourcing notes are in our data documentation on the guides page — values print with their source so you can check us.

Shelf span guide — Sitka Spruce

Longest span that stays at or under the 0.02 in/ft long-term standard, floating ends, load spread evenly:

Shelf	15 lb/ft	25 lb/ft	35 lb/ft
3/4 in thick, 11 in deep	34 in	29 in	26 in
1 in thick, 11 in deep	46 in	38 in	34 in

Quick sag check — Sitka Spruce

Span (in)

Depth (in)

Thickness (in)

Total load (lb)

Full options — edging strips, fixed ends, centered loads — in the Shelf Sag Calculator.

Quick movement check — Sitka Spruce

Width across grain (in)

Cut

From MC (%)

To MC (%)

Full options in the Wood Movement Calculator.