Redwood Lumber Characteristics
The coast redwood, Sequoia sempervirens, is the tallest tree species in the world. Its usual height is 280 to 325 feet, but one specimen has been measured at 360 feet. Their trunks may be 8 to 15 feet in diameter. Redwoods may live for thousands of years, though 600 to 800 years is common. They are found mainly in the Pacific Northwest, with a related species growing in China. Redwood lumber is prized for decks, siding, beams, outdoor furniture and other structures.
Redwood Lumber Grades
Redwood lumber is graded for both appearance and durability. Standards are set by the Redwood Inspection Service. The highest appearance grades are given for wood that is “clear” – meaning free from knots – with further gradations based on the number of knots and any other imperfections present. The color of redwood determines its resistance to decay, the second criterion for grading. The reddish-brown heartwood rates the highest in decay resistance due to natural extracts within the wood; this part of the tree should be used for any structure that will come into contact with the soil, such as structural posts. The light, nearly white-colored sapwood is not as decay resistant. Grades of lumber that include more knots and imperfections are sold for use in decking and outdoor structures such as furniture or fencing, where appearance is not as important as for siding, for example. Commercial siding patterns include shiplap, tongue and groove or plain bevel.
Texture and Patterns
Redwood lumber may be sawn and planed smooth or resawn to leave a slightly rough texture if desired for rustic applications or for siding, where the rough texture serves to hold finishes well and hide marks. Redwood lumber may be cut vertically, so that a cross-section of the growth rings appears on the board face, or tangentially, so that the rings create a marbled pattern.
Like cedar, redwood lumber will naturally turn a silvery gray color over time with exposure to the elements and UV radiation. Redwood will also blacken if exposed to constantly wet climate conditions. To preserve the original red color, the wood should be stained when first installed, then restained every three or four years thereafter.
Redwood bark is commonly used in mulches and potting soil, and at one time was used as insulation. It has also been used for fishing floats and even furniture stuffing. It is soft and stringy, and on mature trees may be up to 2 feet thick. This thick bark covering is a quality that protects the tree from destruction by fire, although the inside of the tree may become hollowed out.
Patricia Rockwood has been a professional copy editor and writer for more than 25 years. She is an avid gardener with a certified Florida backyard habitat. Rockwood has practiced yoga for more than 40 years and taught for much of that time. She is also a professional mosaic artist.