One of the best sealers for wood in the bathroom is spar-urethane.
It’s frequently used on submerged wood, like boat hulls. This particular finish is intended to endure the weather on the hardwood poles that hold a boat’s sails, commonly known as the ship’s spars.
Spar urethane was designed to endure difficult circumstances and preserve the ship’s spars since this piece of wood must withstand severe wetness and wind.
Leslie Scouras