Sustainable Decking Materials

Dear Sam,  I’m looking at replacing my deck this Spring and I’m wondering what type of decking material is most sustainable? -Doug


Hi Doug, Thanks for the timely question!  Spring is sure to arrive soon and we will all be looking to spend more time outdoors.  

An article from Mother Earth News had 6 sustainability factors to consider when choosing a decking material.  If your choice meets 4 out of 6 you can feel ok that it is a sustainable choice:

  1. Local:  Pay attention to how far your decking material has to be shipped.  Locally produced materials are a better choice to cut down on carbon emissions inherent in transportation.
  2. Manufactured Cleanly: Choose a material that is made without the use of toxic chemicals and that doesn’t create any toxic-byproducts.
  3. Sustainable future:  Make sure the product is harvested responsibly and is not a finite resource.
  4. Green Maintenance:  Make sure the product can be maintained without the use of toxic chemicals.
  5. Longevity.  Pick a material that will last as long as possible.  The longer it lasts the less impact it has on the environment.
  6. Recyclable.  Choose a material that can be easily recycled and/or is made from recycled or reclaimed products.

There are basically three types of decking that are most widely used in decking:  wood, vinyl/pvc and composite decking like Trex or Timbertech.  Let’s take a look at each:

Wood.  Wood decking is the most common type of decking as it has been an economical option until recently.  Lumber prices soared during the pandemic and while they have come down, lumber is still a considerable expense when considering a new deck. Wood is long-lasting so long as it is properly maintained.  But wood decking needs to be cleaned and resealed every year or two to maintain its color and prevent splintering and warping.  Unless you choose a hardwood like cedar or redwood (which can be very costly), you will likely be using pressure treated wood for your deck.  This means chemical preservatives have been forced into the wood to increase its longevity.  From a sustainability perspective, pressure treated wood is problematic because of the toxicity of the chemicals injected into the wood.  And, because of the added chemicals, pressure treated lumber is difficult to dispose of properly (landfilling it or burning it releases toxic chemicals into the air and ground). If you choose wood as a decking option be sure to make sure the wood you purchase has been certified by the Forestry Stewardship Council as being sustainably harvested.  In the alternative, choose a wood grown locally to reduce the carbon emissions inherent in transportation of the lumber.

Composite wood. Composite decking is made from wood fiber and plastics.  They are becoming a very popular choice because of the low maintenance and durability.  Most composite decking companies warrant their product for 25-30 years.  Composite decking resists stains, cracks, warping and insects.  While composite decks are low maintenance they will need to be occasionally washed.  And if they are in direct sunlight they can get very hot underfoot.  They can also be slippery.  One last issue with composite wood decking is that, because it is a mixture of two things (plastic and wood) it is difficult to recycle at the end of its life as a deck.  But recycling possibilities are being researched and solutions may be available in the future.  In sum, if you choose a composite wood product that is made with recycled materials (both plastic and wood) composite decks can be a very sustainable option.  So be sure to choose an option that uses only recycled plastic and that gets its wood pulp from scraps instead of cutting down trees.  

Vinyl/PVC.  In general, decking made from vinyl or PVC is going to be the least sustainable option, especially if it is made from virgin plastic.  However, vinyl/PVC decking is inexpensive and doesn’t require the maintenance that wood does.  But it can crack, warp and stain far more easily than composites or wood.  It will also be slippery and very hot in the sunshine.   If you do choose a vinyl/PVC deck, be sure to find one with a high recycled plastic content and ask about its ability to be recycled at the end of its life as a deck.

Now let’s hope the weather cooperates for some great deck weather this summer!

-Sustainability Sam