Coosa Board

Coosa Board is high-density polyurethane foam with reinforced layers of fiberglass. It is truly the premier decking & transom material in the marine industry. There is a reason boat builders put "Certified Coosa Board" decals on their transom! » Read More

What is Coosa Board?

 It's a no-rot composite sheet material primarily used for coring and decking applications.  It’s composed of high-density polyurethane foam reinforced with layers of woven roving and continuous strand fiberglass. It’s structurally superior, doesn’t absorb water, and weighs 30-40% less than marine plywood.

Advantages of Coosa Board

  • 30%-40% lighter than plywood
  • No water rot or insect infestation
  • Less than 1% water absorption
  • Mold, mildew & algae resistant
  • No special maintenance required
  • Sanded for easy lamination
  • Easily fabricated with standard woodworking tools
Coosa board being used to replace the transom in a 1978 Alumacraft bass boat.

Limitations of Coosa Board

Coosa is ideal as a coring material but does have a few limitations. It’s not UV stabilized and will discolor if exposed to direct sunlight; it won’t deteriorate structurally but will become chalky and washed out. 

Additionally, it contains fiberglass which can be rough on bare skin. Therefore, we recommend covering or coating in virtually all applications. Some popular ways to cover Coosa are glassing over it, carpeting, or coating it with latex or enamel-based paints. 

Finally, due to its foam composition, Coosa Board has less screw retention than plywood and should be thru-bolted or secured using special fasteners like stainless steel t-nuts.

What Are Popular Uses?

Coosa is great for structural applications such as:


With 11 CNC Routers and a design team at the ready, all you need is to send a drawing with dimensions or template for your project to Boat Outfitters and let us take the lead. If you’re more of a do-it-yourselfer Coosa composite board is easy to work with using common woodworking tools and can be ordered in third, half, and full sheets.

Our full sheet size is 48” x 96” which is large enough for most projects. If your project is bigger than 96”, like an oversized transom, don’t worry - we can use a puzzle joint to connect two panels for your exact size needs.

Ask an Expert!

Coosa Board is ideal for many applications, but if you’re still unsure if it’s right for your project give us a call at 866-633-7961 and one of our experts can help you decide!

Let Us Help You Decide!

Whether you’re a seasoned DIY-er or someone looking for an already assembled build, Boat Outfitters has a team of experts ready to help with your next project. Give us a call to get your project started! 866-633-7961

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Commonly Asked Questions about Coosa

When replacing plywood decking, what thickness should I use? (show/hide)

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Do I have to encapsulate the Coosa in fiberglass and resin? (show/hide)

What types of resins are compatible with Coosa? (show/hide)

What thickness and sizes are available? (show/hide)

How do I cut Coosa panels? (show/hide)

Can Coosa Board get wet? (show/hide)

Can Coosa Board be bent? (show/hide)

Can Coosa Board be shaved down or shaped? (show/hide)

Can you paint Coosa Board? (show/hide)

Can you fiberglass Coosa Board? (show/hide)

Can Coosa Board be used for boat stringers? (show/hide)
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