How to Install a Mobile & Modular Bathtub

Visually inspect the prepared tub area, paying special attention to the condition of the drain and skirt track. Cut sections of 2-by-4-inch lumber to use for support boards for the tub rim according to the manufacturer's specifications. Mark the wall where you will install the tub rims. Place the scrap pieces at the mark, checking for level. Screw the pieces to the wall with 3 screws -- install one piece per enclosure wall.

Install the new drain into the tub by placing the top section of the drain inside the drain hole in the tub and screwing the large plastic nut to it on the underside of the tub. Use a thick washer or plumber's putty between the drain and the tub. Attach the bottom of the drain to the underside of the new tub, tightening with slip joint pliers.

Set the tub into place with the help of a friend. Rest the tub rim on the support boards while fitting the front of the tub (the skirt) into the skirt track. Attach the tub drain to the drain elbow using an appropriately sized connector. Tighten the nut on the connector or glue around the drain and press tightly against the connection piece.

Look for seams in the wall board to locate the studs. Drill small counter-sunk holes for screws around the tub installation lip. Attach the tub to the wall through the small holes with 1-inch long screws, being careful not to over-tighten.

Prepare your new tub surround by measuring the locations of openings for the faucet and shower (if applicable) and marking them on the material. Apply construction adhesive generously to the walls. Press a 1-piece tub surround into the glue, with the bottom overlapping the tub's installation lip. Pull the unit from the wall, wait 2 minutes, then press it back into place to activate the glue. Install a 3-piece system starting with the largest section first, followed by the back and front, being sure to activate the glue in a similar manner as the 1-piece unit.

Drill 1-inch holes through the front of the tub surround in the previously marked spots. Drill 1/4-inch holes along the edges of the surround as outlined in the installation guide. Dab a little caulk in these holes, one at a time, and press in a plastic rivet. Tap the pop-up section of the rivet with a small hammer until it seats. Install the faucet through the 1-inch holes in the front of the tub and reinstall any shower head or downspout that you may have removed (sometimes these are plumbed high enough they don't require removal).

Caulk the seams of the surround, the joint where the surround meets the tub and all around the surround and tub where they meet the wall. Caulk around the collar of the shower downspout and along the outside of the faucet where it meets the tub surround.