All About Cushion Foam Part 2: 5 Types of Outdoor Cushion Foam

In yesterday’s post, we outlined 4 Important Foam Terms to Know and how those attributes are important to different foam applications. Now that you can talk about foam’s properties and features like a pro, it’s time to take a look at specific types of foam and which of those features they bring to the table. When choosing foam for your next outdoor project, be sure to consider your application and determine which properties are most important for the environment your cushion will live in.

5 Types of Outdoor Cushion Foam

Compressed Polyester

2013_May_29-Nufoam
This is not actually foam, but rather densified polyester batting that creates an effective foam alternative. Compressed polyester will not disintegrate or yellow like traditional foam, but it will compress over time. An example of this is Nu-foam Compressed Polyester, which is mildew resistant and non-allergenic.  Nu-foam is washable, and will easily air dry after getting wet.  This foam alternative is an inexpensive option and is best used for occasional seating, like patio cushions.

Polyester Fiberfill

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Like Compressed Polyester, Polyester Fiberfill is not truly foam, but rather blown polyester fibers. An affordable option, it is a common stuffing for pillows and deep seating back cushions. Generally, Polyester Fiberfill is stuffed inside a pre-sewn cover of Spun Bonded Pillow Protector Fabric, which is then inserted into the cushion or pillow fabric to give support and shape. Fiberfill is non-allergenic, and resistant to mildew. It is machine washable, but the fiber can bunch up in laundering. Use your hand to smooth it back out.

Polyurethane Foam

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A more traditional foam option that often contains a biocide treatment, Polyurethane foam is affordable, has a medium firmness, and is suitable for seating and mattress applications. If polyurethane foam gets wet, the cells will soak up the water. The biocide treatment is important because it prevents mold and mildew growth that can occur when wet foam dries out. It is a good idea to use polyurethane foam in locations where it won’t get wet or to wrap the foam in plastic before inserting it into the fabric. Brands of polyurethane foam include Reflex and Sailrite’s Anti-Microbial Polyurethane Foam. Reflex foam is the most common marine cushion foam.

Open Cell Foam

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An open cell reticulated foam has open pores that allow water and air to flow through easily. Open Cell foams make a comfortable and cool seating cushion or mattress. Dry Fast is a high quality open cell foam. Dry Fast foam is formulated with an antimicrobial agent to prevent mold and mildew. It is a more expensive foam, but you get what you pay for. When paired with an outdoor cushion fabric or Phifertex Mesh, open cell foam creates a virtually maintenance free cushion in sun, rain, and snow.

Dry Fast is a popular, user-friendly open cell foam. Due to its popularity, there are knock-off versions on the market. To see if your foam is high quality Dry Fast foam, pour a cup of water on it. The water should run straight through the foam and drain out the bottom. If the water runs off the sides of the foam, this is an imitation Dry Fast foam.

Closed Cell

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Also known as floatation foam, Closed Cell foam does not allow water to run through, making it buoyant. This foam is made from PVN and is 3 times firmer than Polyurethane foam. It is also a more expensive option. Closed cell foam is great for flotation applications like floating cockpit cushions and life vests. It is also a good choice for commercial boat seating, or other seating that will be used as a step for getting on and off the vessel. This foam has no water absorption, so you can safely cover it with any type of fabric. Thin sheets of closed cell foam are often glued to the bottom of other foam, adding additional support for the cushion, like a box spring to a mattress. When used with Dry Fast Foam, cut holes in the closed cell foam for drainage.

As you can see, there are a lot of foam options out there so it should be no problem to find one that is just right for your next project. Check back tomorrow for the third and final installment in the foam series, Anatomy of an Outdoor Cushion, to see how to wrap and protect the foam inside the cushion.

17 comments
  1. This article really helped me to understand different foam types- which can be very confusing. When I was looking for an outdoor seat cushion for my gazebo, I was debating choosing a foam cushion and a gel cushion. I used bedbathandbeyond.com and seatcushionreviews.com to contrast and compare different options, both foam and gel. Gel ended up being the best option for me, but now that I’m looking to make new cushions for my sunroom, I’ve returned to this excellent article for additional information. Thanks for the great resource!

  2. Michele said:

    Great Information !

  3. Kelly said:

    Hi,
    We built a bed swing for our porch and are looking for foam to use for the seat cushion, the porch is covered so whoever it will get wet at times it won’t be exposed to that much moisture. I wondered what type of foam is you the most comfortable to lay and lounge on?

  4. Kerri Bessey said:

    What is the best type of foam for an interior window seat cushion? I plan to use your sunbrella upholstery fabric for durability and fade resistance qualities. Thx!

  5. Deirdre said:

    This is so interesting. I am curious about the antimicrobial treatment. That kinds of freaks me out to be using a fungicide. Could the polyester compact cushion be used indoors and feel comfortable for everyday use?

    • Nikki said:

      Hi Deirdre,

      The compressed polyester would be great indoors for occasional seating but if you’re doing reupholstery, we’d recommend using a high density polyurethane foam. Those will hold up better to everyday use and they don’t have the biocide treatment added. You can see our selection here: http://www.sailrite.com/Notions/Foam/Upholstery-Foam

  6. Deirdre said:

    Thanks for the idea. BUT, I was thinking I needed an outdoor cushion because it is a window seat at a beach house where the windows are often open. It wouldn’t be direct rain but will get some window spray and will often be in high humid air (NJ in the summer). What is the best option for inside: durable, water resistant
    but also chemical free?

  7. Deirdre said:

    Oh, I am see above that it says “Polyurethane foam OFTEN has a biased treatment”, so I am guessing the high density version does not?

    • Nikki said:

      Hi Deirdre,
      You are correct, the high density polyurethane foam doesn’t have any chemicals added. To protect against the moisture and the occasional rain, you can wrap your foam in Cushion Wrap Silk Film (http://www.sailrite.com/Cushion-Wrap-Silk-Film-Center-Fold-54). This is a noiseless plastic that acts as a moisture barrier. This is combination with the high density foam will give you durability and water resistance without chemicals.

  8. Bee Crandall said:

    What could I use to fuse two layers of compressed polyester together? I have some Elmer’s brand Craft Bond, “acid free multi-purpose spray adhesive” on hand. Would that work okay?

    • Nikki said:

      Hi Bee,
      We’ve never used Elmer’s Craft Bond, so we’re not 100% sure it would work, but since it’s a spray adhesive I’d give it a try. If it doesn’t work, 3M Super 77 Spray Adhesive is what we usually use (http://www.sailrite.com/3M-Super-77-Spray-Adhesive). Let us know if the Elmer’s works for you!

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