Redwood is a remarkable deck material in almost every way; it is very stable, straight, and its heartwood is naturally resistant to wood boring insects and weathering without the use a preservative chemicals. Its fragrant earthy reddish brown heartwood gives it its name. If left unfinished Redwood will initially turn black black and then slowly turn into a silver gray. Its high stability makes it less likely to cup and warp than treated wood. It is prized for its low shrinkage rate, so splitting is minimized. Redwood fastens and machines well but can be brittle; you may need predrill holes at the ends of boards to prevent splitting. Its milled or sanded surfaces accept paint and stain easily. It is recommended that you use a protective finish with a water repellant, mildewcide and Ultraviolet inhibitor.
Redwood can last up to about 30 years on a well-maintained deck under good circumstances. Redwood is the most fire resistant decking material on the market. Its use as building cladding is credited with limiting the Great Fire following the 1906 earthquake in San Francisco. Redwood has been historically the most popular deck material because of these properties. However, because of a limited supply and environmental concerns it is now less available and usually the most expensive option. Also Second Growth trees don’t perform nearly as well as the Old Growth trees that established Redwoods outstanding reputation because they do not possess as high of levels of decay resistance. Redwood decking material is widely available on the West Coast in various sizes and grades, but has very limited availability most everywhere else.