How to Fiberglass Deck Joints

By Danny Donahue

A deck is only as strong as its weakest spot, and the weakest spots of your deck are in the joints. The joints flex and bow as weight is applied and removed throughout the years. This motion loosens the joints and makes the deck unstable. You can reinforce the joints with fiberglass. Wrapping each joint with fiberglass cloth and solidifying it with resin will give your deck much more strength, and add years of life to the structure.

List of Items Needed

  • Fiberglass cloth
  • Staple gun with 1/4 inch staples
  • Shears
  • Fiberglass resin with hardening agent
  • Plastic bowl
  • Plastic putty knife
  • Rotary tool with sanding drum bit
  • Soft, dry rag
  • Spray can of polyurethane
  • Rubber gloves
  • Safety glasses
  • Dust mask
  1. Wrap the entire joint with fiberglass cloth. Staple the fiberglass cloth to the wood on each side of joint. Trim excess cloth with your shears.

  2. Mix fiberglass resin and its hardening agent as recommended in a plastic bowl. Stir the ingredients with your plastic putty knife.

  3. Apply the mixed resin with the plastic putty knife. Coat all of the cloth and the surrounding wood. Smooth the resin as much as possible and let it cure overnight.

  4. Sand the dried resin smooth with the rotary tool. Wipe the sanded resin clean with a soft, dry cloth. Mix a new batch of fiberglass resin and apply a second coat. Let the second coat dry overnight.

  5. Smooth the dried resin with the sanding drum on your rotary tool. Wipe away the dust with a soft, dry cloth. Spray polyurethane onto the fiberglass covered joint and let it dry overnight.

Tips and Warnings

  • Rubber gloves, safety glasses and a dust mask are required when working with fiberglass.

© Demand Media 2011