Foam Series: Selecting the Right Marine Exterior Foam

Item # X-HT-300054

If you’re about to undertake a marine exterior seating project like sailboat cockpit cushions or upholstered powerboat or pontoon seating, the foam you use as the base of your seats is important to the longevity and performance of the whole seat. Choosing foam usually involves a trade-off — it’s rare to find absolutely everything you want in a foam. Instead, it’s better to prioritize the properties and features you hope to find and then select the foam that best suits your needs.

For marine exterior projects where water resistance is a top concern there are two types of foam that we recommend: Closed Cell Foam and Polyurethane Antimicrobial Foam. Let’s take a closer look at which of these types of foam is best for your application.

We have different recommendations for foam based on what type of boat seating you’re making cushions for. Is your project cockpit cushions for a sailboat or upholstered seating on a powerboat or pontoon?

Powerboat or Pontoon Seats

Upholstered seats on a powerboat bridge deck

If you’re upholstering seats on a powerboat or pontoon, we recommend using either Medium Density or High Density Polyurethane Antimicrobial Foam. Polyurethane foam soaks up water, so we don’t recommend using it for cushions that will be covered in a woven fabric; however, since powerboat seats are typically upholstered in vinyl, this is a comfortable and affordable option. The vinyl fabric is waterproof and will keep your foam nice and dry underneath.

Medium Density Polyurethane is the standard foam used by OEM boat builders, while High Density will last longer. It should also be noted that Medium Density is approximately 35% to 40% less expensive than High Density and, therefore, might be a better option for weekend boaters who don't need the longevity and durability of High Density foam. Take a look at our foam product pages to decide whether Medium or High Density Polyurethane Antimicrobial Foam is the right choice for your boat seating.

Sailboat Cockpit Cushions

Cockpit cushions on a Seaward22 Sailboat

For cockpit cushions in a sailboat, we recommend using Closed Cell Foam. We lean toward this type of foam because cockpit cushions often end up in the water and we want to prepare for that possibility. Closed Cell Foam is a great choice for liveaboards and other frequent cruisers because it is a high density (3-5 lbs.) foam and will hold up to daily use for years and years. It is also firm, so it’s great for boats where the cushions are frequently stepped on. A great plus of Closed Cell Foam is also that it floats, so cushions made from it can double as flotation devices. Cover Closed Cell Foam in any type of marine fabric you choose since it’s water-repellent and won’t be hurt by moisture.

Ultimately the choice is yours in regards to which foam you think will best suit your needs. To learn more details about each type of foam mentioned here (and more!) check out our “Comparing Types of Cushion Foam” post (#300053XHT) and “Which Foam Should I Use?” (#300059XHT) flowchart. You can also read more about important terms to know when researching foam in our “5 Important Foam Terms to Know” post (#300052XHT).