POINT/COUNTERPOINT: Treated Wood or Composite Decking

By / 2 years ago
Point/Counterpoint provides equal time to both sides of a controversial topic. This month, we take on the question: What’s Greener: Treated Wood or Composite Decking?


It’s Hard to Beat Nature

Many building materials today are trying to jump on the green bandwagon. Too often, these materials have to create “benefits” that sound environmentally friendly, but fail to stand up to scrutiny.

When it comes to building materials, it’s not easy to match the inherent natural attributes that can be found in wood. In some products, such as pressure-treated wood, those attributes are enhanced to provide products that are safe, easy to use and have a long service life.

The battle over which is greener is taking place in decking products. Treated wood decking has been used for decades, but now other materials such as plastics are claiming they are more friendly to the planet.

When determining the environmental friendliness of a product, however, it’s important to have the facts to back up your claim. The treated wood industry has worked to provide those facts when it comes to decking.

In 2011, a landmark Life Cycle Analysis (LCA) study compared alkaline copper quaternary (ACQ) treated wood decking to composite plastic decking. The peer-reviewed study provided a cradle- to-grave analysis and detailed some real, verifiable environmental differences between the two decking materials.

The LCA study, which followed ISO 14040 and 14044 standards, concluded that treated wood decking had less energy and resource use, lower environmental impacts, less fossil fuel use and more recoverable energy than composite plastic decking.

The energy used in producing plastic lumber is 14 times higher than for treated wood. The fossil fuel footprint of a typical treated wood deck of 320-sq. ft. is equivalent to driving a car 38 miles a year. By comparison, fossil fuel use for a plastic deck of equal size is equivalent to driving a car 540 miles a year, according to the study.

Treated wood decks had significantly lower environmental impacts in five important categories: greenhouse gas emissions, acid rain, smog potential, ecotoxicity and eutrophication-causing emissions. Plastic decks create three times more greenhouse gasses, 4.3 times more acid rain and use almost triple the amount of water compared to wood decks.

The process of pressure treating wood protects the fiber against insects and decay fungi, greatly extending the service life from years to decades. All preservatives used are registered with the EPA and are safe, despite implication by others that they are toxic.

Copper is the primary ingredient in many preservatives to treat wood, the same material jingling in your pocket in the form of pennies. A 12-foot 2×6 board holds the equivalent of 13 copper pennies made before 1982. Ingredients in the ACQ preservative are used in common cleaners like Febreze® or Lysol®.

While these treatments are safe, it still makes sense to use only as much as you need. Treated wood manufacturers have worked diligently to put the right amount of preservative into wood to provide the necessary protection. For example, the industry’s Best Management Practices, or BMP program, has minimized the amount of preservative in products destined for aquatic and wetland environments.

Many products try to emulate the natural attributes of wood (just look at the wood grain pattern molded into composite plastic materials). However, there’s no replicating the extraordinary environmental benefits of wood.

Treated wood has been and will continue to be a versatile, strong and “green” building material. Other products like plastics will try to obscure the natural advantages of wood by appealing to the most popular trend of the day. Yet when you take a closer look, it’s difficult to match the natural benefits of wood.


Click here for thecounterpoint Counterpoint: Composite Wood is a Green Choice.



Dallin Brooks

Dallin Brooks is the Executive Director of the Western Wood Preservers Institute.