Plastic lumber is one of the primary alternatives to traditional wood decking, along with composite decking and aluminum decking. If you're looking for a new decking material that's durable, low-maintenance, and never (ever) needs to be finished—and you don't care much about a natural wood look or texture—plastic lumber might be right for you.
What is Plastic Deck Lumber?
Plastic lumber is made from either recycled plastic or virgin material, typically single resin polyethylene (HDPE and LPDE), polystyrene or polyvinyl chloride (PVC).
It appeared on the building material market in the late 1980s and is available in rectangular cross-sections with dimensions similar to traditional lumber.
Plastic decking is not the same thing as composite decking, which is made of plastic and wood fibers. Plastic decking is just plastic, although it can have any number of additives for resistance to sun damage, scratching, and weather.
Plastic lumber has other applications besides decking, include trim boards, railings, outdoor furniture, siding, and fences. One thing you can't use it for is structural applications, so the support posts, joists, and beams of a deck must be built from a different material (usually wood).
Benefits of Plastic Lumber
Plastic lumber offers many advantages over wood as a decking material:
- Can be molded into many different shapes and sizes, including curves
- Waterproof and resists rot and mold without sealant
- Stain-resistant against many chemicals and substances
- Manufactured in a range of colors and doesn't require paint
- Fade-resistant against the elements
- Does not contain chemical treatments
- Does not splinter, crack, or warp
- Resists insects
- 100 percent recyclable
- Comes with a manufacturer's warranty (often up to 30 years; limited, of course)
Plastic lumber can be cut and drilled just like wood, and no special tools are required. This makes it an option for do-it-yourself installation. It can be screwed down to a wood deck structure, just like wood decking, but many types of plastic decking are designed for hidden-fastener systems that leave the top of the decking unmarred by screw heads.
Keep in mind that plastic isn't able to span as far as wood, and you must provide adequate support for the decking boards. Also, leave room for the plastic boards to expand. For these and other reasons (like maintaining the warranty) it's important to follow the manufacturer's installation specifications to the letter.
Plastic lumber costs quite a bit more than wood decking. It's impossible to provide an average cost, as each project varies in scale, geographic location, and level of detail. Keep in mind that you will recoup a large portion of these upfront costs since plastic deck lumber is so low-maintenance compared to wood and likely will have a longer lifespan.
For an accurate cost comparison with wood decking, factor in the cost of periodic finishing that wood decking requires. Wood decks should be re-stained or sealed every two to three years in most conditions.
The cost of materials adds up, as does the labor or the time (if you're doing the work yourself).
The Question of Aesthetics
While I love how durable this material is, plus the fact that it's recyclable, I don't exactly love the way it looks. In some cases, it can be downright hideous, but in others, it looks pretty decent from a distance. The problem with plastic deck lumber is that the molded wood grain pattern is too perfect and consistent to look real. Why pretend to be something you are not? Fortunately, plastic lumber is available in a variety of textures, and it's possible to avoid the fake-wood wood effect.