This post is part of the Green Materials Report series. GBE is providing information on various building materials and what makes them green. Each post focuses on one material. We will be looking at the ingredients in the material, how it is used, what makes it green, and any green product certifications that it has earned. We hope to develop a database of information to help consumers make informed choices about what goes in their buildings. Enjoy the series!
California Redwood (Sequoia sempervirens) is often used for outdoor structures such as decks and fences. It’s natural ability to withstand weathering and pests make it the perfect material for any project that will be subject to the elements. As far as green materials go, it can’t get much greener than one straight from Mother Earth.
What Makes It Green
Redwood has a lot going for it when it comes to sustainability. It is a renewable resource (it takes 60-75 years for a redwood tree to become harvestable). According to the California Redwood Association we are growing more trees than are harvested, so the supply is guaranteed into the near future. Additionally, much of the redwood harvested is from Forest Stewardship Council (FSC) certified growers and harvesters.
Redwood is a natural material, so it is also biodegradable, and can be returned to the earth as barkdust or wood chips at the end of its useful life. It has also been recognized as a termite-resistant material by the International Building Code.
It is very similar to cedar in its resistance to weather and wear. Other species of wood require chemicals to achieve this resistance. It stays the same dimension after years of wear, a necessary point when dealing with structural members. Both cedar and redwood require no finishing, unless it is desired, and will wear to a weathered gray if left exposed.
Life Cycle Analysis
A life cycle analysis was performed in 2013 comparing California Redwood decking with PVC and other plastic decking materials. Overall, natural decking materials were found to be more sustainable than plastic products in reports like this one: Environmental product declaration for redwood decking.
Pros and Cons
Redwood fares well against other natural products when it comes to cost. It is comparable to cedar, and treated lumber of other types will be less expensive. But when it comes to plastic decking products, the savings really add up. According to Charlie Jourdain, President of the California Redwood Association: “Since redwood is grown and manufactured in California, the further away you get, the higher the price will be due to transportation … not only is plastic decking more expensive per board, but additional substructure is required due to the weight and lack of strength, further adding to the increased overall cost of such a deck. Combine this with studies that show that a redwood deck has an increased resale value over a plastic or composite deck and redwood’s value becomes even more obvious.”
Redwood structures will last for years without fear of pests, weathering, or wear. If a new finish is desired, the existing wood can be sanded down and restained.
Alternative decking materials are made from petroleum-based plastics that are not good for the environment. Many of these plastics come from foreign countries, thus adding to the carbon emissions produced by using them. Redwood and other natural materials provide a positive impact on the environment while they are growing, and require little processing. Transportation does add some carbon to the equation, since it can only be found in California.
Redwood can be allowed to age and weather naturally, or a finish can be applied to protect it from the elements and provide or preserve color. These finishes do need to be reapplied every few years. On the other hand, plastic decking materials are practically maintenance free, except for routine cleaning.