How to Build a Raft

Nothing is more relaxing than a float down a river. Perhaps you have a fishing rod in one hand and a cool drink in the other. Constructing a raft is a good do-it-yourself project that will get you on the water quickly.

Required Materials

  • marine foam
  • 2×10” pressure-treated lumber
  • bolts
  • ratchet
  • screws
  • decking
  • paper/pencil

Required Tools

  • knife
  • circular saw/table saw
  • drill with full bit set
  • hammer

Instructions

  1. Size and Weight – The two most important things to consider when building a raft are weight and the raft’s intended use. Bigger and heavier rafts are good for swimming, but a raft for a river needs to be easily transportable and hence small and lightweight. The building techniques are generally the same whatever your choice.
  2. Layout - A raft of any kind is a fairly simple project. Putting together all the materials and tools is perhaps the most difficult task. The major thing to remember with a raft is that the bigger the width and length you choose, the more stable the raft.
  3. Cutting Materials - The raft will be 15×15’. Start by cutting eight 2×10” boards in half and then attach them to eight 2×10” full length boards with 2×4” blocking. Screw them together with galvanized or marine screws, making sure to countersink the heads. Now is the time to be working near the water.
  4. Assembly - Attach side boards to treated 2×4” blocking at the third and middle positions of the raft. This will create a two-board wall with a 1” space between. Attach four side walls together with blocking and screws. Number and screw the corner blocking in place. Size your marine foam and locate floor joists along the side walls. Then cut floor joists to a 7’ length. Attach a 2×10” board section across the box from center point to center point. Attach the floor joists as needed, being careful to notice areas where sharp corners, metal pieces, or screws may be present. The use of 2×4” marine lumber floor joists may be heavier than is ideal.
  5. Cutting the Foam - Use marine foam or other flotation materials to fill the spaces between the floor joists. Marine foam has the best float, followed by ’home center’ foam and general ’floaties’. With foam products, a knife or a hot wire is a good tool for cutting and shaping.
  6. Decking - Once the raft proper has been built, decking can be considered. It can range from plywood to 2×10s. Here you will need to decide between weight, durability, and practicality.