How to Replace a Corner Bathtub

Corner bathtubs maximize bathroom space while providing a comfortable soaking area, but when they wear out or leak, replacement becomes essential. This comprehensive guide walks you through every phase, from assessing your space to final testing, ensuring a sturdy, water-tight installation that enhances your home’s functionality and aesthetics.

Assessing Your Bathroom Setup

Before diving into demolition, evaluate the current configuration. Measure the existing tub’s dimensions, typically 60×60 inches for standard corner models, and note the drain and faucet positions. Check if the new tub matches these specs to avoid major plumbing relocations. Inspect walls for water damage or mold, as corner tubs often trap moisture in tight angles. Verify floor joist strength, since these tubs weigh over 200 pounds when filled. Use a stud finder to map framing, and confirm access to shut-off valves for water supply lines.

Gather details on local building codes, which may require permits for plumbing alterations. Corner installations demand precise alignment with two adjacent walls, so photograph the setup for reference. If the tub integrates with a shower surround, plan for compatible replacements to prevent gaps.

Essential Tools and Materials

Prepare a toolkit suited for heavy lifting and precise plumbing work. Key items include a reciprocating saw, pry bar, hammer, channel-lock pliers, pipe wrench, level, tape measure, safety glasses, gloves, and a shop vac. For installation, stock up on plumber’s putty, silicone caulk, adjustable feet or mortar bed mix, ledger board, screws, and a strainer wrench.

• Demolition tools: Utility knife, oscillating multi-tool, drain snake.
• Plumbing supplies: PVC fittings, PEX tubing, flexible siphon, O-rings.
• Finishing materials: Foam seal strips, masking tape, joint smoother.

Opt for high-quality acrylic or AcrylX tubs with integrated flanges for easier tiling. Budget for potential professional help on drain modifications if your setup involves galvanized pipes.

Removing the Old Corner Bathtub

Start by shutting off water supplies and draining the tub completely. Remove faucet handles and spouts using a wrench, then detach supply lines. Access the drain from below or via an access panel.

Unscrew the overflow cover plate with a screwdriver, followed by the drain assembly and strainer. Use penetrating oil on rusted fittings. For stubborn flanges, employ a strainer wrench or cut the pipe if necessary. Disconnect the waste-and-overflow (WO) unit with pliers, lubricating joints or slicing plastic pipes as needed.

Cut away caulk and sealant around the tub edges with a utility knife. Score drywall or cement board up to the flange line. Insert a pry bar under the tub lip and hammer gently to break the seal. Fiberglass corner tubs often lift after freeing all sides—roll it out carefully to avoid floor damage. Clean debris and inspect subfloor for rot; reinforce if required.

Preparing the Space for New Installation

With the old tub gone, level the subfloor using self-leveling compound. Frame alcove supports if switching tub styles, but for direct replacements, focus on drain alignment. Ensure the drain hole is within 80 cm of the new tub’s plug position.

Install or adjust the WO unit. Test-fit the tub without feet attached. Mark wall studs for a ledger board, positioned just below the flange height to bear the tub’s weight during tiling. Screw the 1×4 board securely. Protect walls with cement board up to the rim for moisture resistance, avoiding standard drywall.

Installing the Drain and Plumbing Components

Position the new tub’s drain shoe into the overflow tube and connect to the main line. Apply plumber’s putty under the drain flange, press it into the tub bottom, and secure with a gasket and strainer. Tighten using a wrench from inside the tub.

For corner models, attach a flexible extra-flat siphon hose with seals and O-rings. Screw connections hand-tight, then test by filling the tub and checking for leaks into a placed basin. Connect water supplies—copper, PEX, or multilayer—near pre-drilled faucet holes, ideally by a licensed plumber for code compliance.

Positioning and Leveling the Tub

Place the tub in the corner, leaving a 1 cm gap under the apron for expansion. Check level on all sides using a 4-foot level. Adjust feet by loosening nuts, raising or lowering, then retighten. Bed the base in mortar for stability, preventing flex that leads to cracks.

Confirm the tub is plumb against walls. Apply foam seals 5 mm from surround edges to buffer movement. Secure the drain hose to the floor sleeve with a multi-material connector and clamp.

Sealing and Waterproofing

Run masking tape along joints where surround meets walls and tub. Cut sealant nozzle at 45 degrees and apply even silicone beads, preferably with the tub filled for optimal adhesion. Smooth with a tool, remove tape immediately, and allow 24-hour curing.

Install tub surrounds—prefer one-piece units for simplicity. Measure and jigsaw cutouts for faucets. Screw into studs every 15 cm, caulk all perimeters with bathroom-grade silicone. Use cement board behind for tile-ready surfaces.

Final Connections and Testing

Mount faucets into pre-drilled deck holes. Reconnect supplies and test flow. Fill the tub multiple times, checking every joint for drips. Run water for 10 minutes post-caulk cure. Inspect floor and walls for moisture.

Tile up to the flange, silicone the tile-tub joint. Your corner bathtub is now ready for years of use.

Common Challenges and Solutions

• Uneven Floor: Shim feet or add mortar bed.
• Rusted Drains: Cut and replace with PVC.
• Tight Spaces: Use reciprocating saw for precise cuts.
• Heavy Lifting: Enlist help or use furniture sliders.

Frequently Asked Questions (FAQs)

Can I replace a corner tub without removing walls?

Yes, if dimensions match and plumbing aligns, minimizing demo.

How long does installation take?

2-3 days for DIY, including drying times.

Do I need a plumber for the drain?

Recommended for complex rerouting to meet codes.

What’s the best material for corner tubs?

AcrylX or acrylic for durability and easy cleaning.

How to prevent future leaks?

Use quality seals, test thoroughly, and bed in mortar.