How to Install a Whirlpool Tub
Few things are as relaxing as a soak in your bathtub. Now, with the help of our how-to instructions, you can have a whirlpool tub in your own home.
Add major luxury to your bathroom with a whirlpool. A tub's not overly difficult to install, but it is a fairly time consuming project. Before you begin, find out what type of tub you have and whether it needs to be framed.
Some whirlpool tubs or spas have a finished side or two, so framing and finishing the side panel are not required. Rectangular models install much like a standard tub, except that a GFCI electrical receptacle is required. Triangular whirlpools fit into a corner. If the whirlpool has an integral spout, follow the manufacturer's instructions for running supply lines to the unit.
Large whirlpools are heavy when filled with water, so you may need to strengthen the floor by adding joists. Check the whirlpool's instructions and local codes. Ideally, it's best to lay flooring after the tub is framed and installed but before any tiling is done.
A whirlpool needs an extra access panel to reach the electric pump. A 2x4 frame is covered with backerboard, then tiled. The whirlpool's flange rests on tile, but the tub's weight must be supported by a mortar bed.
Set aside two or three days to frame, install, and tile a whirlpool tub. Before you start you'll need to measure the space carefully, taking into account the framing, backerboard, and tile thickness.
What You Need
- Carpentry tools
- Groove-joint pliers
- PVC saw
- Wiring tools
- Tiling tools
- Putty knife
- Adjustable wrench
- Whirlpool tub
- Waste-and-overflow unit
- Lumber and screws for framing
- GFCI receptacle
- Cement backerboard with screws
- Mortar mix
- Pipe-thread tape
Step 1: Build the Frame
Build a frame following manufacturer's directions. It's especially important to get the height right. You may snug the whirlpool up against one, two, or three walls. Where you snug the tub against the wall, attach a 2x4 ledger as you would for a standard tub. Where you will install tiles, plan the framing carefully, taking into account the thickness of the backerboard and tile. Most whirlpools require access to the plumbing at one end and the pump motor at the other end; check the manufacturer's directions.
Step 2: Cut and Attach Backerboard
Cut strips of cement backerboard to fit where needed on top of the framing. Backerboard pieces should overhang the framing by 1/2 inch. You also can cut the side backerboard pieces, but don't install them yet. Attach the backerboard using special backerboard screws.
Step 3: Check for Fit
Cut several spacers 1/8 inch thicker than the tiles you will install. (For 1/4-inch-thick tiles, cut pieces of 3/8-inch plywood.) Set the spacers on top of the backerboard wherever there will be tile. Set the whirlpool in place and see that it fits. Be sure the bottom of the tub is at the correct depth so it will rest on the mortar bed.
Step 4: Check Drain Trap Position
Check to make sure the drain trap is positioned at the correct height so the whirlpool waste-and-overflow unit will slide into it. Plan how you will make this connection, either from the basement or crawlspace below or through the access panel.
Step 5: Assemble Waste-and-Overflow Unit
Assemble the waste-and-overflow unit. Some whirlpools come with a waste-and-overflow; if not, you'll have to purchase a standard unit and add an extension. Insert the shoe (cut to length if necessary) into the tee fitting.
Step 6: Tighten Nuts
Set the tub on two overturned buckets. Install the overflow by slipping in the plunger assembly, tightening the screws on the cover plate, and screwing the drain flange into the shoe. Tighten the nuts on the drain extension.
Step 7: Mix Mortar
Test-fit the whirlpool to see that the waste-and-overflow unit will slip into the drain trap. Remove the whirlpool. Screw 2x2s to the floor around the drain hole to keep mortar out of the hole. In a bucket or wheelbarrow, mix water with dry mortar mix. The mortar should be just wet enough to be poured. Smooth enough mortar onto the floor to support the bottom of the whirlpool.
Step 8: Set the Tub
Place spacers on the backerboard atop the side-panel frame. With a helper, gently set the tub in place. Guide the waste-and-overflow into the drain trap but do not tighten the connection. Push down on the tub until the lip rests on the spacers, but do not press hard. Allow the mortar to harden overnight.
Step 9: Connect to Drain
Connect the waste-and-overflow to the drain and tighten the fittings. Support the pump motor with pieces of lumber and attach it in place with screws. Plug the cord into the GFCI receptacle. Follow the manufacturer's instructions for testing the whirlpool.
Step 10: Install Backerboard
Install cement backerboard on all exposed sides. Drive backerboard screws every 6 inches or so. Wrap corners with fiberglass mesh tape.
Step 11: Add Tiles
Apply thinset mortar using a notched trowel and set standard tiles on the side. When tiling the top edge, use bullnose caps for the outside corner for a finished look. After the thinset has dried, apply grout and clean the joints. Caulk the joint where the whirlpool rests on the tiles.
Step 12: Install Showerhead
Once the wall is finished, remove the temporary nipple at the showerhead location. Wrap pipe-thread tape around the ends of the shower arm and screw it into place. Slip on the flange. Twist on the showerhead. Protect chrome with tape before tightening the showerhead with an adjustable wrench and groove-joint pliers.
Step 13: Attach Faucet
Following manufacturer's instructions, slide the escutcheon over the faucet and screw it into place. It should seal against the tiles with a rubber gasket. Attach the faucet handle.
Step 14: Attach Spout
Apply caulk around the spout hole. Choose a nipple of proper length for the spout and wrap pipe-thread tape around the threads on both ends. Thread the spout on by hand. Finish by wrapping the spout with a rag and tightening it with groove-joint pliers.