How a Milk Jug Becomes an Adirondack Chair

Originally Published on April 23, 2018. Last Updated on May 25, 2022.

In celebration of Earth Day, we’re giving you an inside look at how we take ocean-bound and landfill-bound plastic and turn it into beautiful outdoor furniture.

A Little History

Since the 1950s, the mass production of disposable plastic has rapidly increased. Unfortunately, plastic is extremely slow to degrade — scientists still don’t know exactly how long plastics will exist after they end up in a landfill. 

While we as consumers can make a difference by recycling our plastics, it’s important to know which plastics can and cannot be reused (a little more on that later).

birds flying over landfill

At POLYWOOD we recycle high-density polyethylene (HDPE for short), an extremely durable type of plastic you’ll find all around your home. Milk jugs, detergent containers, shampoo bottles, lotion bottles, cleaner spray bottles, etc. are all made from HDPE. The best part about HDPE is that it can actually be infinitely recycled. Yes, infinitely.

If all of those empty HDPE containers in our lives make it into the recycling bin they’ll have a chance to become something new — and, they might just travel to a little town called Syracuse, IN to become an Adirondack chair.

Our Recycling Process

First, HDPE plastic containers arrive at our recycling plant bundled in large bales.

flattened milk jugs in bales

The flattened plastics are sent up a conveyor to a giant shredder to be pre-shredded.

recycling milk jugs process



Next, the shredded plastic flakes are pre-washed and any heavy materials that might have gotten mixed in (glass, rocks, etc.) are removed.


The cleaned and sorted material is then finely ground into a 1/2″ flake and sent to a float tank where any other non-plastic items will sink out of the mix. The flakes are then dried and air separated.


Next, our color sorter will remove any colored plastics we don’t want mixing into the final product. Once sorted, the resulting good material travels up another conveyor to be pelletized.


The final product, shown below, is loads of clear pellets that are ready to be made into genuine POLYWOOD lumber!


Making Genuine POLYWOOD Lumber

The recycled pellets are transported next door to the Extrusion Department by an efficiently designed series of tubes from one building to the next. All pellets are stored in silos outside the building and then sucked in through more tubes that run right to our extrusion lines.

Tubing that runs from the Recycling Building over to the silos outside of the Extrusion Department.
Our silos that store recycled plastic pellets waiting to become POLYWOOD lumber.

While we can’t divulge every step of the process, we take our recycled pellets, add colorant, along with other additives (to ensure beautiful long-lasting color), and then extrude the mixture to the size and shape of the lumber we need (similar to when you “extruded” Play-Doh as a kid).


In a day, we extrude about 48,000 to 55,000 pounds of lumber. That equals about 57,000 to 60,000 pounds of landfill-bound and ocean-bound plastic — and that’s just in one day!


Constructing POLYWOOD Furniture

On the last leg of its journey, our HDPE lumber makes its way to our production cells where our team constructs POLYWOOD furniture.




Remember we mentioned that HDPE is infinitely recyclable? After our furniture is made, any scrap lumber pieces, shavings, etc. from manufacturing go right back to our recycling plant to be reground, sent to extrusion, made into lumber, and, well, you know the rest.

Zero waste, pretty cool right?



Plastics by the Numbers

While HDPE plastics are easily recycled, some plastics are not accepted by most curbside recycling programs (pickup availability will vary depending on your location). Below is a cheat sheet on the seven plastic codes so you can brush up on your recycling knowledge.

Plastic Recycling Chart

A few tips:

  • Avoid products that use plastics with recycling symbols 3, 6, and 7. While number 1 is considered safe, it’s best to avoid.
  • Look for plastics with symbols 2, 4, and 5, as these are considered to be the safest (especially around food and beverages).

For more information on each plastic type, check out

We can all make better choices when it comes to the products we purchase (and recycle) — let’s treat every day like it’s Earth Day!

Blog Post Updated April 29, 2021

24 thoughts on “How a Milk Jug Becomes an Adirondack Chair

  1. Great informative information! Have you guys ever considered making porch and deck railings/balusters/columns? My personal experience is the wood solutions rot over time and require painting maintenance to keep things looking good. Using your material seems like it would be a once and done scenario? I am redoing a porch this summer and will incorporate your rocking chairs and some tables to “fix” that part of the project : )

    Thanks for what you do.

    1. Thanks for the kind words Jonathan!

      There are definitely companies out there who use a similar all-weather material for decking solutions, but we’ve stuck to furniture.

  2. Love them, such a wonderful concept. We own 3 over the past 3 years we added 1 each year to our yard.☀️

  3. I love your products! We have six bar stools in mahogany and they are perfect for our bar in the kitchen. We have a cat sanctuary and would love to have some cat trees made that same material. Do you make such an item, if not would you consider doing so?
    Thank you!

    1. Hi Debbi,

      As a cat person myself, I LOVE that idea! But, we’ve decided to stick to outdoor furniture for now. If you’re feeling up to it (or know someone who could build one) you can purchase a similar all-weather material from the following suppliers:

      We don’t currently sell PW lumber, but you can purchase a similar material from these suppliers:

      Allied Plastic Lumber in CA – 916-469-8639

      Plastic Lumber Yard in PA – 610-277-3900

  4. Can you show us a “declassified picture” of a plank being extruded? Pleeeeease? My inner nerd wants to see it! Thanks for this writeup!

    1. Hi Dave,

      Well…you can see a bit of the process in our brand video at the 20 sec mark. Hopefully that satisfies your inner nerd!

  5. Pingback: 6 things you can recycle in Deschutes County that you didn't know you could. - Rethink Waste Guide | Reduce, Reuse, Recycle, Deschutes County
  6. I am looking for the approximate number of milk jugs it takes to make one full sized rocking chair? I want to be able to brag about the recycling benefits we have from our new furniture.

    Thank you very much,

    1. Hi Mike,

      Great question!

      It will take approximately 600-800 milk jugs to create a chair. It is such a neat way to use recycled material.

      Have a wonderful day!

  7. You are a great example of being environmentally responsible. Can you tell me how much of the plastic that goes into a piece of furniture is recycled plastic?

    1. Hi Richard!

      We can’t say exactly because this varies from board to board, but it’s not 100%. We would certainly use 100% post consumer recycled plastic if we could, but sourcing enough post-consumer material is difficult. So much of the material we could be using here in the US has been shipped to other countries. In an effort to incorporate as much post-consumer material as possible and continue in our effort to keep both the ocean and landfills clean, we’ve partnered with organizations like The Plastic Bank.

      Thank you for taking the time to ask.

  8. I have a few questions I’m curious about. (Apologies in advanced for how critical some of these sound.)
    1- What do you do with all the colored plastic that is “unworthy”? Does it just go to the landfill?
    2- Why only milk jugs? Or do you use all #2 plastics? And if you use all, why only #2 plastics?
    3- You say you can’t use 100% consumer recycled plastics – is that because the demand for your chairs is so high? If less people purchased your chairs would you focus on making a higher percentage of the chair recycled plastic and creating less new plastic waste?
    4- Are your chairs recyclable themselves? Can you break them down to remake chairs?

    1. Hi Sarah,

      Thank you for reaching out to us with your questions! We’re happy to help.

      1. We use the colored plastic that we receive in the extrusion of our lumber as well. It will go through a different run than the clear pellets.
      2. We use all number two plastics in the extrusion of our lumber. We get bails of milk jugs, but there will also be laundry detergent bottles, shampoo and conditioner bottles, etc included. We use #2 plastics because they are durable and make for strong furniture.
      3. We use post industrial materials as well as post consumer because post consumer materials are difficult to find. So much of the material we could be using here in the US has been shipped to other countries. We use as much post consumer materials as possible in the extrusion of our lumber.
      4. Our furniture is recyclable. We add all of the scraps from our furniture during the production process back into the extrusion process.

      Thank you for taking the time to ask your questions!

  9. We have a swimming with a sundeck that is approximately 4” deep. We would like to leave a pair of chairs on the sundeck pretty much year (south Florida, all year is swim season). Would it be acceptable to keep Polywood in water continuously?

    1. Hey Paul!

      Thank you so much for taking the time to ask this great question! If it were for a short period of time that would be alright, but we do not recommend keeping your POLYWOOD Furniture submerged constantly.
      Take care!

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