How to Relocate a Toilet Drain Pipe

The toilet drain pipe can be relocated, but it must be done carefully depending on the relocation distance and the type of bathroom. Here are the specific methods:

I. Short-Distance Relocation (within 40 cm)

1. Use Specialized Tools
   • Flat Relocation Device: Suitable for "fine-tuning" within 15 cm. It is essentially a plastic pipe with a slope that reduces space occupation.
   • Round Pipe Relocation: For relocations around 20 cm, tools such as a 110 mm drain pipe, an adapter pad (choose to keep or remove based on the original pipe material), and an upper drainage 110 elbow are required to ensure interface tightness.
2. Maintain Slope
   The pipe needs to maintain a slope of 1%-2% (i.e., a drop of 1-2 cm per meter). A steeper slope reduces odors, but the floor will form a small slope of "low in the front and high in the back." Communicate with the tiler in advance to adjust the tile-laying method.
3. Reduce Elbows
   Avoid using too many elbows to prevent blockages caused by restricted sewage flow.

II. Long-Distance Relocation (over 40 cm)

1. Raise the Floor
   The floor needs to be raised by about 20 cm, and the pipes need to be relaid. The standard diameter of the drain pipe is 110 mm, but in practice, it needs to be raised by at least 120 mm to ensure that the pipe can bend without blockage. After adding a cement mortar leveling layer, it is recommended to raise it by 15 cm for greater safety.
2. Install a Water Trap
   Install a water trap at the end of the pipe to maintain a water seal height of ≥50 mm and prevent odor backflow.

III. Special Case Handling

1. Sunken Bathroom: The pipes can be freely modified, but cast iron pipes need to be clamped tightly with a hoop and coated with sealant.
2. Same-Floor Drainage: There is no need to damage the floor slab, and modifications can be decided independently.
3. Inter-Floor Drainage: Approval from the property management and signatures from neighbors are required.
4. When the floor load-bearing capacity allows and waterproofing is in place: An 110 mm hole can be made in the floor slab above the original drain pipe, and the new pipe can run along the wall to achieve zero floor elevation, but signatures from the downstairs residents are required, and the floor slab structure must be sturdy.

IV. Precautions

• Construction Timing: The installation of the relocation device must be completed before tiling. Otherwise, tiles need to be cut or the floor needs to be raised, increasing construction difficulty.
• Tool Selection: When purchasing a relocation device, measure the center distance between the original sewage outlet and the drain pipe accurately. It is better to be longer than shorter to avoid later cutting.
• Floor Treatment: It is recommended to lay sloped tiles in the raised area to prevent water accumulation. If a threshold stone is installed at the doorway, an expansion joint should be embedded to prevent deformation due to thermal expansion and contraction.
• Professional Construction: Be sure to have a plumber or electrician position the pipes. An error of more than 1 cm may puncture the steel bars, leaving safety hazards.
• Closed Water Test: After construction, a 48-hour closed water test should be conducted to check the waterproofing effect.