How to Build a Jacuzzi Bathtub Skirt

Sketch out your plans for the completed bathtub skirt so you have a precise idea of its optimal height, width and depth. Carefully measure the thickness and materials you plan to use for the completed skirt, and sketch and note all dimensions, as creating your design is the main challenge of the project.

Account for the height of the skirt including the distance from the lip of the tub to its bottom flange, as well as the 1-inch depth of your mortar bed underneath. Note the thickness of the marine-grade plywood on the top of the skirt, typically 3/4 inch; of the concrete backer board and its thinset mortar, typically 5/8 inch; and of the tile and its thinset, typically 3/8 inch. If you are finishing the top of the skirt with other materials, such as teak or Corian, measure these materials and estimate the thickness of adhesive to be used.

Calculate the width and length of the skirt, tailored to your preferences. For example, you can design a size that uses uncut full tiles of 4, 6, 8 or 10 inches or multiples thereof, if your whirlpool basin is oval but set in a rectangular apron that can be tiled evenly. If the apron itself is oval, you can cut a waterproof laminate surface instead or cut each tile to fit.

Cut 2-by-4s to create a sole plate for the frame, outlining the length and width of your design, and screw them to the subfloor. Cut identical 2-by-4s to serve as a top plate. Cut studs long enough so that when installed between the sole and top plates, the top plate can be covered with plywood, tile or alternate coverings exactly to the lip of the whirlpool. Toenail studs in place at the corners and every 16 inches along the bottom plate. Screw the top plate on top of the studs.

Lay marine-grade plywood on top of the top plate and screw it in place. Mark an outline of the tub lip on the plywood. Drill a pilot hole and cut out the outline with a jigsaw.

Create spacer blocks out of scrap wood equal to the thickness of your planned coverings, such as cement backer board and mortar. Mix and trowel mortar on the subfloor to support the whirlpool. Place the spacer blocks around the edge of the cutout. With an assistant, lift the whirlpool over the skirt framing and set it on the mortar base, supported by the spacers.

Screw cement backer board to the sides of the frame and to the plywood top if you plan to finish the skirt with tile. Place 3/4-inch plywood across two studs as an access panel to the pump and finish with paint, molding or tile that does not cover its screws. Complete the surfaces of the skirt with tile or an alternative covering.