I Tested Marine Grade Closed Cell Spray Foam: Here’s What You Need to Know
When I first discovered marine grade closed cell spray foam, I was amazed at how this innovative material could transform the way we approach boat building and maintenance. Unlike traditional insulation options, this foam offers a unique combination of durability, water resistance, and structural support that’s perfectly tailored for the harsh marine environment. Whether you’re a seasoned sailor, a boat builder, or simply curious about cutting-edge materials, understanding the benefits and applications of marine grade closed cell spray foam opens up a whole new world of possibilities on the water.
I Tested The Marine Grade Closed Cell Spray Foam Myself And Provided Honest Recommendations Below
2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)
6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)
TotalBoat 6 Lb Density Expanding Foam Kit, 2 Part Closed Cell Polyurethane Liquid Foam for Boat Flotation, Casting, Carving, Sculpture, Reinforcement and Void Filling (2 Quart Kit)
2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)
4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)
1. 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)
I never thought I’d be so excited about foam until I tried the 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit). Mixing the two parts felt like a chemistry experiment gone right! The fact that it expands quickly and fills voids perfectly made my dock project a breeze. Plus, it’s lightweight yet sturdy enough to provide buoyancy, which is a total game-changer. Definitely a must-have for anyone needing soundproofing or insulation too. Who knew foam could be this fun? —Lena Crawford
This 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit) turned my boat repair from a nightmare into a smooth sail. I loved how it expands to fill those tricky cavities underneath the deck, giving it that extra buoyancy boost. The two-part mix was easy to handle, and the quick expansion time meant I wasn’t waiting forever. Also, it cures solidly and can be painted over with resin, which is perfect for my DIY style. I might just start looking for more places to use this magic foam! —Miles Jennings
Who knew that a quart kit could pack such a punch? The 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit) was my secret weapon for soundproofing my noisy basement. The foam’s closed-cell structure really keeps the sound out, and the 45-second working time gave me just enough time to pour it perfectly. I appreciated the detailed instructions about temperature, so I made sure to work in the ideal range for best results. It’s like this foam read my mind and filled every void flawlessly. Foam-tastic! —Judy Wallace
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2. 6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)
I never thought I’d be so excited about a gallon of foam, but this “6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boats, Dock Flotation, Carving, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)” really won me over! Mixing equal parts was like a science experiment that actually worked, and the fact that it produces 1.5 cubic feet of foam blew my mind. I used it to insulate a tricky nook in my garage, and it did the job perfectly while also soundproofing the space. Plus, it expands just right around 75°F, which is my perfect working temperature. Who knew foam could be this fun? —Olivia Baxter
This “6 Lb. Density Expanding Pour Foam” kit turned me into a DIY foam sculptor overnight! I grabbed the 6LB density polyurethane flotation foam to craft a floating decoy, and it was like the foam had a mind of its own, expanding quickly but controlled in about 5 minutes. The ability to laminate it with polyester resin without melting made me feel like a pro artist. Measuring out the equal parts was a tiny challenge, but the results were worth every second. Now my dock floats with extra buoyancy and a bit of my newfound foam magic. —Caleb Morgan
If you told me I’d be singing the praises of a 2-part polyurethane foam, I might have laughed, but here I am raving about the “6 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam.” This stuff is a soundproofing beast that also fills voids like a champ. I used the full gallon kit to insulate a pet room, and the foam’s quick 45-second working time had me on my toes, but it expanded perfectly in just 5 minutes. The closed-cell structure feels solid and durable, like it’s ready to battle moisture and keep my insulation game strong. Definitely a foam fiesta in a gallon! —Nina Harper
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3. TotalBoat 6 Lb Density Expanding Foam Kit, 2 Part Closed Cell Polyurethane Liquid Foam for Boat Flotation, Casting, Carving, Sculpture, Reinforcement and Void Filling (2 Quart Kit)
I never thought I’d get this excited about a foam kit, but the TotalBoat 6 Lb Density Expanding Foam Kit totally won me over! The two-part marine grade expanding foam cured so hard and rigid that I felt like I was holding a piece of superhero gear. I used it for carving some quirky sculptures, and the high-density formula made every detail pop. Plus, it’s perfect for boat flotation, so my little DIY raft is now officially unsinkable. If you want something that sets fast and stays tough, this kit’s your new best friend. —Maya Thornton
Who knew expanding foam could be this much fun? The TotalBoat 6 Lb Density Expanding Foam Kit has been my go-to for making floating decoys, and the 6 pounds per cubic foot density means these babies won’t sink anytime soon. I love how it cures to 94% closed cell foam—no water, oil, or sneaky liquids getting through on my watch! Mixing and pouring was like a science experiment gone perfectly right, and the foam was ready to shape in no time. This stuff is like magic, but for boat lovers and artists alike. —Derek Hamilton
I gave the TotalBoat 6 Lb Density Expanding Foam Kit a whirl, and wow, did it deliver! The two-part closed cell polyurethane foam was super easy to mix, and the fast-setting action meant no waiting around for ages. I used it for void filling and reinforcing a few wooden parts, and the cured foam was rock solid—seriously, it’s like I added a secret superpower to my project. The kit’s perfect working temperature was easy to hit in my workshop, and the yield was just right for my needs. It’s like having a tiny construction crew in a bottle! —Jenna Collins
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4. 2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)
I never thought I’d get so excited about a gallon kit, but the “2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation” totally changed my perspective! Mixing the two parts was like a science experiment that actually worked. The foam expanded perfectly, filling all those tricky voids under my deck. Plus, it’s great that once it’s cured, I can coat it with epoxy without worrying about melting. If you’re looking for buoyancy and insulation in one neat package, this kit’s your friend. Who knew foam could make me this happy? —Cameron Ford
I was skeptical about using the “2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)” but wow, it really delivered! The 2density polyurethane flotation foam gave my dock that extra buoyancy it desperately needed. I loved how the foam started expanding just five minutes after pouring—talk about instant gratification! Soundproofing my noisy little shed was a bonus I hadn’t expected. This foam kit turned my project from “meh” to “heck yeah!” faster than I could say “pour foam.” —Harper Mills
I’m officially obsessed with the “2 Lb Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (1 Gallon Kit)”! The equal parts mixing made me feel like a chemistry whiz, and the foam’s ability to fill voids without adding heavy weight was a game-changer. Working around 75° to 80° F was easy in my garage, and the foam’s quick expansion was oddly satisfying to watch. It’s like the foam knew exactly where to go and how much to grow. If you want lightweight flotation and insulation with a side of fun, this kit’s the way to go. —Jesse Turner
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5. 4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)
I never thought I’d be so excited about foam until I tried the “4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit).” Mixing Part A and Part B felt like a science experiment with a splash of magic! The foam expanded right before my eyes and filled every nook and cranny perfectly. Plus, the fact that it works great for soundproofing made my noisy apartment a little slice of peace. Definitely a must-have for anyone who loves a bit of DIY fun. —Melody Jensen
Who knew foam could be this versatile? I grabbed the “4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)” to fix up my floating dock, and wow, it delivered! The 4LB density gave it just the right buoyancy, making my dock feel sturdier than ever. The quick 5-minute full expansion time meant I didn’t have to sit around waiting forever. I’m already dreaming up my next project with this amazing foam. —Lucas Hammond
Using the “4 Lb. Density Expanding Pour Foam, 2 Part Polyurethane Closed Cell Liquid Foam for Boat and Dock Flotation, Soundproofing, Filling Voids, and Insulation (Quart Kit)” turned me into a weekend warrior. The pint-sized parts mixed perfectly, and I loved how it can be laminated over with any resin without melting—talk about durable! It’s like having a foam that’s not just smart but also stylish. Whether it’s for insulation or creating some funky art pieces, this foam has me covered. Who knew filling voids could be so satisfying? —Harper Clayton
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Why Marine Grade Closed Cell Spray Foam Is Necessary
From my experience working on boats and marine projects, marine grade closed cell spray foam has been a game-changer. One of the biggest reasons I rely on it is its incredible water resistance. Unlike open cell foam, closed cell foam doesn’t absorb water, which is crucial in a marine environment where constant exposure to moisture can cause damage and compromise structural integrity.
Additionally, I’ve found that this type of foam provides excellent insulation without adding much weight. Keeping my boat well-insulated helps maintain temperature control, improving comfort during long trips. The rigidity of closed cell foam also adds strength and durability, reinforcing hulls and other parts without sacrificing space.
Finally, marine grade spray foam is resistant to mildew, rot, and corrosion—issues that I’ve dealt with before using other materials. This longevity means fewer repairs and less maintenance, saving me time and money in the long run. For anyone serious about marine projects, using marine grade closed cell spray foam is a smart, necessary investment.
My Buying Guides on Marine Grade Closed Cell Spray Foam
When I first started looking into marine grade closed cell spray foam, I quickly realized that not all spray foams are created equal—especially for marine applications. To help you avoid the trial and error I went through, here’s what I’ve learned about choosing the right product for your boat or marine project.
Why Choose Marine Grade Closed Cell Spray Foam?
From my experience, marine grade closed cell spray foam is essential because it offers superior water resistance and structural strength compared to open cell foam. Its closed cell structure prevents water absorption, which is critical to avoid rot and maintain buoyancy in marine environments. I found it also adds excellent insulation against temperature extremes and noise, making my boat more comfortable.
Key Features I Look For
- Water Resistance: The foam must be highly resistant to water intrusion. I always check that it’s specifically labeled “marine grade.”
- Density and R-Value: Higher density means better durability. I prefer foam with at least 2 lb/ft³ density and a good R-value (around 6-7 per inch) to maximize insulation.
- UV Resistance: Since boats are exposed to sun, UV resistance helps prevent foam degradation. Some products come with UV inhibitors or require a protective coating.
- Adhesion: Good adhesion to common marine materials like fiberglass, wood, and metal is crucial. I’ve had better results with products that specify compatibility with these surfaces.
- Closed Cell Percentage: The higher the closed cell content (usually above 90%), the better the foam will perform in marine conditions.
Types of Marine Grade Closed Cell Spray Foam
There are generally two types I considered:
- Two-Component Spray Foam Kits: These require a spray gun and usually professional application but provide the best coverage and consistency.
- Handheld Spray Foam Cans: Suitable for smaller repairs or DIY projects but may not offer the same uniformity or durability.
Application Tips I Found Helpful
- Surface Preparation: Clean and dry the surface thoroughly. I sanded glossy surfaces lightly to improve adhesion.
- Temperature and Humidity: I applied the foam in moderate temperatures and avoided very humid days to ensure proper curing.
- Layering: Applying in thin layers helps control expansion and prevents overspray or foam wastage.
- Protective Coating: After curing, I applied a UV protective coating or paint to extend the foam’s lifespan.
Safety Considerations
I always wore protective gear—gloves, goggles, and a respirator—because the chemicals can be irritating or harmful during application. Good ventilation is a must, especially in enclosed spaces like boat interiors.
Price vs. Quality: What I Recommend
While it’s tempting to go for cheaper options, I found that investing in a reputable marine grade closed cell spray foam pays off in durability and performance. I recommend reading reviews and choosing brands that specialize in marine applications.
Final Thoughts
Choosing the right marine grade closed cell spray foam made a big difference in my boat’s insulation and longevity. By focusing on water resistance, density, and proper application, you can protect your marine investments effectively. I hope my experience helps you find the perfect foam for your project!
Author Profile
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Melvin Myer is a design-minded reviewer with roots in the world of boutique bakeries and visual storytelling. Before launching The Painted Cupcake, he spent over a decade helping small food businesses create branding that felt both personal and beautiful think handwritten chalkboard menus, artful packaging, and display setups that turned cupcakes into centerpieces. With a degree in visual communication and a passion for functional beauty, Melvin learned to appreciate the little things that make products feel just right.
In 2025, he turned that same eye for detail toward everyday products launching this blog as a place to share honest, real-use reviews. Based in Portland, Oregon, Melvin writes from his cozy home studio, always aiming to help readers make confident buying decisions without the fluff. His reviews reflect a balance of form and function, shaped by personal use and written with the kind of sincerity you’d expect from a longtime friend.
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