Redwood

Sequoia sempervirens (D. Don) Endl. · Softwood · North America

Janka 480 lbf≈25 lb/ft³ dried (est.)Very durable

Properties

Janka hardness	480 lbf (2,135 N)
Average dried weight (est.)	25 lb/ft³ (400 kg/m³)
Specific gravity	0.40
Modulus of rupture	10,000 psi (69.0 MPa)
Modulus of elasticity	1.34 million psi (9.24 GPa)
Crushing strength	6,150 psi (42.4 MPa)
Shrinkage — radial	2.6%
Shrinkage — tangential	4.4%
Shrinkage — volumetric	6.8%
Shrinkage T/R ratio	1.7

Values at 12% moisture content, clear-wood averages. Source: USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282 (2021), Table 5-3 p. 5-13; shrinkage Table 4-3 p. 4-8.

Redwood is a moderately lightweight softwood (specific gravity 0.40, Janka hardness 480 lbf) whose old-growth heartwood is highly resistant to decay, the property behind its use in decking, tanks, silos, and cooling towers. Most redwood lumber goes into building, siding, and millwork.

Appearance & grain

The heartwood ranges from a light cherry red to a dark mahogany. The sapwood is narrow and almost white. Typical old-growth wood is generally straight grained.

Durability

Old-growth heartwood is highly resistant to decay; second-growth heartwood rates only low to moderate.

Workability

Old-growth redwood is moderately strong and stiff and moderately hard, and it is easy to work. It shrinks and swells comparatively little: its volumetric shrinkage of 6.8% is the lowest in this set.