How to Repair Fiberglass Boat Floors
Nothing will ruin a nice afternoon on the water like a hole or tear in the bottom of your boat. Fortunately, there are many products available on the market that will repair and strengthen the hole or tear. The process is quite simple and you will soon be back on the water.
Required Materials
- fiberglass mat
- fiberglass gel coating
- Bondo
- supports if curved piece
- sandpaper
- cleaning agents
Required Tools
- orbit sander
- scraper
- scissors
- tape measure
- coping saw/jig saw
- cleaning supplies
Instructions
- Gaining Access - If you are dealing with a boat floor, you may have access issues. Ideally, you will like to repair the fiberglass floor from the back side of the floor. Unfortunately, this is not possible in some instances. If access is possible, remove any storage or equipment before starting work.
- Cutting a Clean Edge - A clean fiberglass edge is preferred to one that is ragged. Unless the floor area is structural, cut out the damaged section to get a smooth edge that will take the repair.
- Cleaning the Site - Fiberglass epoxy requires a clean surface for best adherence. Clean the surface of all impurities. Remember that not all marine impurities are visible to the human eye, so clean diligently. Try not to use agents approaching the level of bleach - these will act in a poor way with the fiberglass epoxy. Make sure that the site is dry after cleaning.
- Supports - If the site is of a curved nature, you may need some supports to make the repair (see fiberglass box article). Cut support shapes from the plywood and tack them together.
- Apply Backing Layer - Begin by roughing up the fiberglass around the damaged section. A steel brush should suffice. This will give the epoxy something to attach to. Next, cut a piece of the sheet fiberglass, allowing approximately 3” overlap of the damaged section.
- Curved Floor - If the damage involves a curved section, form a foam shape that approximates the curve and cover with Bondo to match the curve. Sand the Bondo smooth. Do this in thin layers for best results. Lay the fiberglass sheet over the Bondo and apply epoxy to form the desired shape. After the shape is cured, fiberglass the shape in place with several layers of fiberglass. Sand the new shape smooth.
- Exposed Side - Once the backing support is in place, make sure the facing side is clean. Cut the fiberglass to include approximately 3” overlap of the damaged area. Lay out the fiberglass and epoxy to the underside support and the deck. Make sure to remove any bubbles or wrinkles from the wet fiberglass mat. This is very important for a finished look.
- Sanding - Sanding is perhaps the most important aspect of a fiberglass repair. Begin with a 400-grit paper and move up as the surface is smoothed. Be sure to clean the surface between grits. You want a smooth surface that closely matches the existing floor and has a certain amount of traction. If painting is involved, sand beyond what you would normally consider smooth, as paint will magnify any inconsistencies.
