Redwood
Light, stable softwood with natural decay resistance. Used for decking, siding and outdoor structures where a long unprotected service life matters more than strength.
Properties
- Family
- Wood
- Category
- wood
- Species
- Sequoia sempervirens
- Density
- 0.42 g/cm³ · 420 kg/m³
Densityhow redwood compares
Wood propertiesUSDA clear-wood values at 12% moisture content
- Species measured
- Old-growth redwood (Sequoia sempervirens)
- Specific gravity
- 0.4
- Janka side hardness
- 480 lbf · 2,135 N
- Modulus of rupture
- 10,000 psi · 68.9 MPa
- Modulus of elasticity
- 1.34 ×10⁶ psi · 9.24 GPa
- Shrinkage, green to oven-dry
- 2.6% radial · 4.4% tangential · 6.8% volumetric
Old-growth. The young-growth timber is lighter and weaker — SG 0.35, MOR 7,900 psi, 420 lbf.
Source: USDA Forest Service, Wood Handbook — Wood as an Engineering Material (FPL-GTR-190, 2010), Table 5–3b, for clear straight-grained specimens at 12% moisture content. The grey figures are converted at 1 lbf = 4.448 N, 1 psi = 6.895 kPa and 1 GPa = 145,038 psi; the inch-pound numbers are the published ones. Specific gravity is oven-dry mass over volume at 12% moisture content, so it sits about 12% below the working density at the top of this page (0.4 × 1.12 ≈ 0.45 g/cm³). The two come from different sampling programmes, so a few species differ by more than that.
Applicationswhere redwood is normally specified
Appearance & workabilitytrade experience, not measured values
- Origin
- Coastal California
- Appearance
- Reddish-brown heartwood, straight grain, fine texture
- Working
- Soft and easy to work. Old-growth grades are more decay resistant and more stable than the young-growth timber.
Unlike the USDA figures above, these lines are not measurements: they carry no units and no single source. They describe how the timber is generally found to behave rather than what it is guaranteed to do — read them as the consensus of the trade, not as a specification.
Practical notes
- Density is for air-dried stock at about 12% moisture content
- Soft surface — it takes marks and dents readily
Lumber sizeswhat redwood weighs in each nominal size
Lumber size databaseDressed sizes are the same for every species — a 2x4 is 1-1/2 x 3-1/2 in in oak as much as in spruce. What changes is the weight, and that is derived here from redwood's density of 0.42 g/cm³.
Tools used on itmatched on the wood family, not on this page
All toolsWhich tools work a material is a property of the family (Wood), not of the individual species — so this list is the same on every wood page, and changes when the tool data changes rather than when this paragraph does.
Frequently asked questionsthe questions this page answers about Redwood
How hard is Redwood?
Janka hardness is 480 lbf — the force needed to push a steel ball halfway into the wood. Higher is harder; this is the number quoted when a wood is specified for floors, worktops or butcher blocks.
How dense is Redwood?
Density is 0.42 g/cm³, and the USDA table gives a specific gravity of 0.4.
How much does Redwood move when it dries?
Green to oven-dry it shrinks 6.8% by volume — 2.6% radially and 4.4% tangentially. Movement across the grain is what opens joints, so a species that moves a lot wants room to move.
What is Redwood used for?
Typical uses are Decking, Siding, Fencing and Outdoor structures.
How does Redwood work with hand and machine tools?
Soft and easy to work. Old-growth grades are more decay resistant and more stable than the young-growth timber.