Best Fiberglass Cloth for Boat Floors

When it comes to repairing or rebuilding your boat floor, choosing the right fiberglass cloth is a critical step. Your boat’s deck takes on a lot — from heavy foot traffic to exposure to water, sun, and temperature changes. That’s why using high-quality fiberglass cloth ensures not only a smooth finish but also long-lasting durability and structural integrity.

In this post, we’ll break down the best fiberglass cloth options for boat floors, why they matter, and what you should consider before starting your next project.

Why Fiberglass Cloth Matters for Boat Floors

Fiberglass cloth is the backbone of any good fiberglass layup. It adds strength, prevents rot, and provides a solid foundation for resin to bond. For boat floors, the cloth must be:

• Strong and impact-resistant
• Moisture and rot-resistant
• Easy to work with for layering and contouring
• Compatible with polyester or epoxy resin

Best Types of Fiberglass Cloth for Boat Floors

1. Woven Roving (Heavy-Duty Strength)

Best for: Large floor areas needing high strength.

Woven roving is a coarse, heavy fiberglass fabric, typically used in conjunction with chopped strand mat (CSM). It provides excellent structural strength and is ideal for thick layers.

• Weight: Usually 18 oz. per square yard
• Best used with: Polyester or epoxy resin
• Pro tip: Alternate layers of CSM and woven roving for a strong, balanced layup.

2. Chopped Strand Mat (CSM)

Best for: Bonding layers and filling gaps.

CSM is made from short strands of fiberglass randomly distributed and held together with a binder. It's easy to work with and great for creating thickness and strong bonds between structural layers.

• Weight: Commonly 1.5 oz. or 2 oz. per square foot
• Best used with: Polyester resin (binders can inhibit epoxy adhesion)
• Pro tip: Use CSM as your base layer, then build up with woven or biaxial cloth.

3. Biaxial Fiberglass Cloth (+/- 45° Weave)

Best for: High-performance, structural reinforcement.

Biaxial cloth offers strength in multiple directions, making it a favorite for boat floors and stringers. It drapes easily, bonds well with epoxy resin, and requires less resin than woven roving.

• Available with or without a CSM backing
• Best used with: Epoxy resin for superior bond
• Pro tip: Biaxial fabric with stitched mat (1708) is a go-to choice for many boat restorers.

4. Fiberglass Cloth (Plain Weave)

Best for: Finishing layers and lightweight reinforcement.

This is the most basic form of fiberglass cloth and is often used as a finishing layer due to its smooth texture. It doesn’t provide as much strength as other options but gives a clean, professional look.

• Weight: Typically 6 oz. or 10 oz.
• Best used with: Epoxy or polyester resin
• Pro tip: Use this on top to finish off your layup for a clean sandable surface.

Tips for Working with Fiberglass Cloth on Boat Floors

• Surface Prep is Key: Remove all rot and dirt before laying fiberglass.
• Use the Right Resin: Epoxy resin is stronger and more water-resistant, while polyester is more affordable and easier to sand.
• Work in Layers: Alternate between different fiberglass types to maximize strength.
• Don’t Skip Safety: Always wear gloves, goggles, and a respirator when working with fiberglass and resin.

Recommended Products to Get Started

Looking for premium fiberglass cloth and all the supplies you need? Check out our selection at Boat Suppliers:

• Fiberglass Cloth & Resins Collection
• Epoxy and Polyester Resins
• Boat Flooring & Repair Supplies

Final Thoughts

Choosing the best fiberglass cloth for your boat floor isn’t just about picking the thickest material — it’s about selecting the right combination for strength, flexibility, and durability. Whether you're doing a full floor replacement or a small repair, investing in quality materials will pay off for years to come.

Need help deciding which fiberglass product is right for your project? Browse our full range of fiberglass supplies or contact our support team at Boat Suppliers for expert advice.

Happy boating — and even happier building!