Can a Bathtub's Exterior Be Wrapped?

Building a Bathtub Skirt

• A bathtub skirt helps hold the insulation wrap in place and protects the insulation from moisture. To build a bathtub skirt, miter sections of two-by-four at 45-degree angles to form two rectangular plates. Cut another four sections of two-by-four, about 4 inches shorter than the finished height of the skirt. Connect the lumber sections with 4-inch wood screws. Set one plate on the floor around the bathtub, and attach the four height studs to the bottom plate at the corners with 4-inch wood screws at 45-degree angles. Set the top plate on top of the height studs and insert 4-inch wood screws through the top plate at the corners to secure it to the studs. Cut and attach 1-inch-thick decking planks to the sides of the frame with 2-inch wood screws.

Applying Insulation

• Apply foam insulation to the underside of the bathtub. Foam insulation comes in pressurized cans, and expands to fill the space between the bathtub and the floor. Apply foam insulation between the sides of the bathtub and the skirt. After you have completed the insulation, cut and install 1-inch-thick decking boards along the top of the frame around the top edge of the bathtub.

Waterproofing the Skirt

• You need a sealant to prevent water from damaging the insulation. Apply waterproof sealant to the exterior of the skirt with a paintbrush. Allow the sealant to dry for two hours, then apply a second coat. Apply caulk along the seam between the bathtub and the skirt to provide additional protection against moisture.

Considerations

• Although foam insulation can provide heat transfer resistance to help keep your bath water warm, it also adheres to the sides of the tub and the skirt. If you decide you want to remove the skirt and insulation, you will also have to remove the bathtub. Also, avoid using fiberglass insulation, which absorbs moisture more readily than foam insulation. If there is a leak between the bathtub and the skirt, moisture can compromise the insulative properties of fiberglass insulation.