Replacing a bathtub in a small bathroom can dramatically improve both the appearance and functionality of the space. Whether your current tub is stained, cracked, outdated, or simply no longer meets your needs, installing a new bathtub can give your bathroom a fresh look while increasing your home’s value. While this project requires some plumbing knowledge and careful planning, many experienced DIY homeowners can successfully complete a bathtub replacement with the right tools and preparation.
This guide explains how to replace a bathtub in a small bathroom, including the tools and materials you’ll need and step-by-step instructions to help you complete the project safely.
Step 1: Measure the Existing Bathtub and Bathroom
Before purchasing a replacement tub, carefully measure the existing bathtub’s length, width, and height. Small bathrooms often have limited maneuvering space, so verify that the new tub can fit through hallways, doorways, and the bathroom entrance.
Most standard alcove bathtubs are 60 inches long, but dimensions can vary. Taking accurate measurements helps avoid installation problems later.
Step 2: Turn Off the Water Supply
Shut off the water supply to the bathroom before beginning any demolition work. Open nearby faucets to relieve pressure and drain any remaining water from the lines.
If your bathroom has dedicated shutoff valves, use those. Otherwise, turn off the home’s main water supply.
Step 3: Remove Fixtures and Drain Components
Remove the bathtub faucet, handles, shower trim, spout, drain cover, overflow cover, and any surrounding accessories.
Use the appropriate drain removal tool or wrench to disconnect the drain assembly. Carefully disconnect any accessible plumbing connections beneath or behind the tub.
Step 4: Remove Surrounding Wall Materials
Most bathtub replacements require access to the wall framing around the tub.
Using a utility knife and pry bar, remove tile, fiberglass panels, or other wall materials extending approximately 12 to 18 inches above the tub flange. Be careful not to damage plumbing lines or electrical wiring hidden within the wall cavity.
Once the wall materials are removed, inspect the framing for signs of water damage, mold, or rot.
Step 5: Remove the Old Bathtub
After disconnecting the plumbing and exposing the tub flange, remove any screws or nails securing the tub to the wall studs.
If the tub is fiberglass or acrylic, it may be possible to remove it in one piece. Cast iron tubs often require additional labor and may need to be cut into sections for removal.
With assistance, carefully lift and maneuver the old bathtub out of the bathroom.
Step 6: Inspect and Prepare the Installation Area
With the old tub removed, inspect the subfloor, wall studs, and plumbing connections.
Repair any damaged framing or subfloor materials before proceeding. Ensure the floor is level and clean. Verify that the new bathtub’s drain location aligns with the existing plumbing.
This is also an ideal time to upgrade plumbing components if necessary.
Step 7: Install the New Bathtub
Place the new bathtub into the alcove and carefully position it according to the manufacturer’s instructions.
Use a level to confirm the tub is perfectly level from front to back and side to side. Install shims where needed to achieve proper alignment.
Once positioned correctly, secure the bathtub flange to the wall studs using approved screws or fasteners.
Step 8: Connect the Plumbing
Install the new drain and overflow assembly according to the manufacturer’s directions.
Apply plumber’s putty where required and use plumbing tape on threaded fittings. Reconnect the drain lines and verify that all connections are tight.
Turn the water supply back on and test the tub for leaks before closing the walls.
Step 9: Repair the Walls and Surround
Install cement backer board around the tub area to provide a moisture-resistant surface for tile or wall panels.
Finish the surrounding walls with your chosen material and seal all joints according to the manufacturer’s recommendations.
Step 10: Apply Caulk and Complete Final Checks
Apply a continuous bead of high-quality silicone bathroom caulk where the tub meets the walls and floor.
Allow the caulk to cure fully before using the bathtub. Perform a final inspection to ensure all fixtures operate properly and no leaks are present.
Important Considerations for Small Bathrooms
Replacing a bathtub in a small bathroom can be more challenging than in larger spaces due to limited working room. Carefully planning the removal and installation process can help prevent damage to walls, doorways, and flooring. Additionally, bathtub weight, plumbing modifications, and waterproofing requirements can make this project more complex than many homeowners initially expect.
