How to Install a Bathtub Yourself
Since a bathtub is a fairly large item (and if made of cast iron, also heavy), it's best to have a partner when installing it yourself.
Required Materials and Tools
The correctness of installing a bathtub yourself largely depends on whether all materials and tools are prepared in advance. Their selection depends on the specifics of installing a particular type of bathtub (cast iron, acrylic, steel). For DIY work, you will need:
- cement mortar;
- insulation tape;
- sealant (preferably silicone);
- polyurethane mounting foam;
- oil-based paint;
- bathtub fitting kit;
- drain hose (for cast iron pipes - 40.0 mm, for plastic pipes - 50.0 mm);
- rubber sleeve for cast iron pipes (40.0 x 50.0 mm);
- drain valve assembly;
- construction level, measuring tape, ruler;
- pen;
- set of screwdrivers;
- self-tapping screws with anchors;
- hand saw;
- hammer;
- chisel;
- adjustable wrench #2;
- construction adhesive gun;
- power drill (with hammer function), angle grinder.
Preparation Work
Installation specifics of a bathtub depend on its type: cast iron, acrylic, or steel. The best option is a cast iron bathtub, which, despite its significant weight, retains water temperature well, is reliable, stable, and long-lasting. Second-best are acrylic bathtubs, known for low cost, light weight, and good thermal retention.
However, it’s better to avoid steel bathtubs or only purchase them in extreme cases, as they lag behind in almost every aspect. Also, when choosing a bathtub, consider its dimensions and room size: ideally, at least 0.9 m of free space should be left in front.
Before starting plumbing work, including bathtub installation, first shut off the water supply valve on the riser, then drain any remaining water from the pipes. Next, remove the old bathtub. Difficulties may arise when disconnecting a cast iron bathtub from the drainage system.
Usually, the bathtub’s drainage and overflow fittings are removed using a chisel and hammer, or cut with an angle grinder. The old bathtub is typically not needed. However, it’s recommended to try unscrewing the overflow nut and drain flange.
Removing an acrylic or steel bathtub is simpler, as the plastic fittings are easily detached. Then, remove the feet with a hammer, turn the bathtub on its side, and carefully carry it out, avoiding contact with water supply taps and washbasin.
Then check the condition of the drainage pipes. Clean cast iron and steel joints to bare metal inside, wipe dry, and temporarily cover openings to prevent debris from entering. Remove all construction debris from the bathroom.
Installing the New Bathtub
Carry the bathtub carefully into the room and lay it on its side near the installation spot. Ensure the drain hole faces the drainage pipe. Attach the feet to the bathtub and place it in position. You can use brick supports or a combination of feet and bricks instead of standard feet—especially recommended for lightweight acrylic bathtubs.
Once in place, use a construction level to precisely check the bathtub’s level. Adjust using adjustment mechanisms (clamps) on standard feet, locking pins, or properly aligned bricks.
Occasionally, bathtubs are installed slightly recessed into the wall. This prevents water from seeping between the wall and bathtub. To recess a bathtub into the wall, use a drill to cut a groove along a pre-marked line.
Seal the gap between the bathtub and wall with mounting foam, apply waterproof paint, and finish with decorative tiles or plastic trim. Additionally, regardless of placement, attach a special profiled tape along the edges that touch the wall to dampen sound vibrations and wall resonance.
Connecting the Bathtub to Drainage
As per the instructions included with the bathtub’s drain-overflow kit, assemble the drainage system. Connection to the drainage system is done only after the bathtub is securely fixed in place. When assembling, carefully place conical rubber gaskets at all connection points. All joints must be further sealed with silicone sealant.
For plastic drainage: insert the drain hose into the bell joint.
For steel drainage: wrap the part of the hose that will go into the bell joint with insulation tape to the required diameter.
For cast iron drainage: insert the rubber sleeve into the bell joint, then insert the drain hose into the sleeve.
Wrap the hose-to-joint connections for plastic or steel pipes with special insulation tape. Again, seal all joints with sealant.
Checking Seals for Leaks
After the sealant has dried, test the assembled system for leaks. Close the drain opening with a plug and fill the bathtub with water to about one-quarter full. Wrap all joints with toilet paper for inspection. Place toilet paper under the drainage fitting. Remove the plug.
If the toilet paper stays dry, the installation was correct. Otherwise, recheck and reseal any leaking joints until complete watertightness is achieved. Only then can you proceed with bathroom room waterproofing.
