The Loma Prietan
July/August 2002
Building a "Green" Deck in Your Yard
by Sherri D. Osaka
Open any gardening or home improvement magazine and you will find advertisements for composite wood decking materials. You've heard the names: Trex®, Easy Care Decking, Nexwood™, TimberTech®, and more. They sound good. They recycle waste products into a usable decking material that doesn't rot. But how good are they really for the environment and what effect will they have on future generations?
Wood Composites
Wood composites are made of waste fiber from lumber milling or agricultural processes, and polyethylene (PE) or high-density polyethylene (HDPE) from plastic grocery bags and milk containers. The fiber is mixed with the plastic and molded into boards for a decking material that bugs won't eat, doesn't warp or splinter, and requires no maintenance.
You think, "Great. I get a maintenance-free deck that will last a couple of decades and I recycle materials as well. What could be better?" The problem is that once the waste fiber is encased in plastic, it almost never breaks down. Insects, fungus, and microbes can't get at these fibers in order to decompose them, creating a problem of how to dispose of them when they reach the end of their useful lives.
Natural and Technical Materials
William McDonough, founding principal of the architecture firm William McDonough and Partners and a leader in the field of ecologically intelligent architecture, defines two basic types of materials in the world: "natural" and "technical." Natural materials are derived from nature and include wood, rice hulls, wool, cotton, etc. They are easily disposed of because they harmlessly break down into the duff of the forest floor from where they came.
Technical materials are mined from the earth, such as petroleum, mercury, and metals. They should be recycled by humans in a technical metabolic system that continually creates new products so these resources don't pollute the earth.
According to McDonough in an October 1998 Atlantic Monthly article, "In order for these two metabolisms to remain healthy, great care must be taken to avoid cross-contamination. Things that go into the technical metabolism should be kept well apart from the biological metabolism." At the EnvironDesign2 conference in the spring of 1998, McDonough gently admonished the organizers for giving away bags made from a blend of cotton and recycled plastic: a mixing of natural and technical materials.
Wood composite decking is also a mixture of these two types of materials: plant fibers from trees and grains, and polyethylene from petroleum. Once mixed together, the base materials can no longer be separated out. We can no longer put the polyethylene back into the technical recycling system of product manufacture, nor can we put the wood back into the natural recycling system that Mother Nature devised.
Trex Co. purchased more than 200 million pounds of recycled PE and equal amounts of waste wood in the year 2000. While we should applaud their efforts to keep these tons of PE out of landfills, we should balk at their taking millions of pounds of waste wood and preventing it from decomposing as well.
Mixing together these two materials, Trex Co. produced something like 400 million pounds of Trex in the year 2000 alone. This is just one of the manufacturers of wood composite products. How much do the others pump out every year? What is going to happen to all this material when home owners eventually tear out these decks?
A Nexwood brochure states, "Why should you spend your precious weekend time caring for and maintaining your wooden deck? With Nexwood you can build it and forget it. Enjoy yourself!" Our children may wish we spent less time enjoying ourselves and more time maintaining a wood deck that will eventually degrade.
The confederacy of six Native American tribes, known as the Iroquois, believed that, "In every deliberation we must consider the impact on the seventh generation." These tons of wood composite products may save our current generation some time, but may have a negative impact on future generations when they try to dispose of them.
Seventh Generation Decking Solutions
Instead of wood composites, consider solid wood decking. Redwood is always beautiful and is locally grown. Ipe (pronouced "ee- pay") is a Brazilian hardwood known for its strength and rot resistance.
Either wood makes a beautiful deck, but select only materials that are certified by the Forest Stewardship Council (FSC) as sustainably harvested to be sure you are not supporting clear cutting and other harmful lumbering methods. Two lumberyards that deliver FSC-certified wood to anywhere in the Bay Area are Big Creek Lumber and Hayward Lumber.
Another solution is to use decking materials made solely from technical resources. Carefree® Building Products are manufactured from recycled HDPE and according to their information are 100 percent recyclable, so they can be used over and over again. Durawood decking products are also made from recycled HDPE.
Perhaps some day manufacturers will make wood composite products from soybean-derived plastics that will naturally decay over time as wood does. Or perhaps they'll figure out how to separate the plastic from the wood so that both materials can be continually recycled. Until then, decking from purely natural or technical materials is best for ecology-minded consumers and provides a seventh generation solution.
Sherri D. Osaka writes about ecological topics and is owner of the landscape design firm
Sustainable Landscape Designs.