How to Replace Fiberglass Boat Flooring

A small, fiberglass boat docked in a marina at sunset.
  • 10-20 hours
  • Intermediate
  • 500-2,000
What You'll Need
BC plywood sheets
Electric saw
Carpenter square
Fiberglass matting
Measuring tape
Electric screwdriver

Fiberglass boat flooring replacement is a common procedure that a lot of boat aficionados perform to restore their boats and keep them in good shape. After years of use, flooring can get damaged, particularly if left exposed to all weather conditions for a long time. Therefore, it will need replacing. Here are some steps to follow and a list of the tools and materials required in order to do this successfully.

Step 1 - Remove the Damaged Flooring

The most common material used for boat flooring is BC plywood, and it is also used for fiberglass boats in particular. Start removing the old damaged material using an electric saw to cut it; if the stringers and bulkheads are rotten, get them replaced with fiberglass ones. Then, unscrew the center console box and the seat with an appropriate screwdriver and disconnect the center console from the cables. Remove any other remaining connections as well and get the console and the seat out of the way.

Step 2 - Add new Stringers

If you are also going to replace the stringers, make sure to take good measurements. Each side can slightly vary, so it’s better to take separate measurements for each stringer by using a tape measure. Then, use the electric saw to cut the stringers from the plywood sheet and fit them in the boat. Screw them all together to create a solid frame and apply fiberglass matting all over it for waterproofing.

Step 3 - Install the Deck

It is always recommended to cut the deck flooring into separate sheets so that it will be much easier to install. Measure the size of the deck and determine how many sheets you'll need of material. Then, cut square holes in the sheets for all the fittings on the deck in the appropriate areas.

Start placing the deck sheets when you're done making your cuts. Each time you lay a sheet, pass the cables and the other connections through the square holes before placing the next one.

Step 4 - Finish the Deck

Once the deck is in place, attach the sheets together with screws so it will all be in one piece. As with the stringers, apply fiberglass matting all over the deck to make it water-resistant. Finally, fasten the deck with some screws at the boat edges and apply a sealant so that no water will penetrate it.

Step 5 - Reconnect the Wiring and Secure the Seats

With the deck has been replaced, you only need to reconnect the wiring, so place the center console in place, connect it with the cables, and screw it in place. Position the seat next and fasten its screws. Start the engine to check whether or not the center console is properly connected.

Now the flooring should be properly installed and the boat ready for another trip. This job can be a rather difficult one if you don’t have any experience with wood cutting, however, so contact a carpenter to cut the plywood for you if you can't.