You are wise to seek alternatives to wood. Logging practices and the manufacture of wood products deplete forest resources, and many wood products are treated with harmful pesticides.
I have seen recycled and composite plastic lumber used successfully as alternatives: both are durable and are not treated with wood preservatives.
Although "plastic lumber" may sound oxymoronic, it has numerous positive attributes, though it does not have the natural-looking grain and color variability that make wood unique.
- Pricing for plastic lumber is competitive with high-end wood decking, but it's not as inexpensive as standard materials.
- Plastic lumber's big story is its durability, with some manufacturers offering warranties of 10 to 20 years.
- Another plus is that plastic lumber does not have to be stained or sealed. Routine maintenance is much less costly and labor intensive than for wood decking.
- Plastic lumber is rot resistant, stands up well to graffiti and other forms of abuse, and is not on the menu for wood-consuming pests.
Standard woodworking tools can be used for constructing plastic lumber decks. Plastic lumber is available in many colors, ranging from outrageous to more subtle hues, with simulated wood grain. UV-stabilized colorants are added to slow fading, and some products can also be painted.
Recycled plastic lumber
Plastic for decking lumber can come from many plastic resins, such as PVC, polystyrene, and HDPE (high-density polyethylene). Avoid plastic lumber made from PVC; it is not healthy or sustainable.
Instead, choose HDPE, which usually comes from post-consumer milk jugs rather than virgin plastic.
Refer to this PDF chart from the Healthy Building Network, which lists popular plastic lumber products by the type of plastic and the percentage of post-consumer recycled content they contain.
Composite plastic lumber
Some plastic lumbers are composites that use fiberglass as reinforcement, or use a blend of rubber and wood fibers. One of the most popular decking alternatives is a blend of preconsumer wood chips (from manufacturing waste) and plastic resins.
- This option is not considered true plastic lumber, nor is it quite as rot resistant, but it is stronger because of the wood fiber component.
- See the Healthy Building Network's ranking of environmentally preferable plastic lumber products for more information; composite products on that list are those that contain "FG" (fiberglass), wood and other nonplastic components.
Although composite plastic lumber products were tested for flammability in 2002 and received favorable results, new fire code amendments in California restrict the use of these materials in fire-prone areas of the state, beginning in 2008.