How to Change Drainage When Moving the Toilet

The methods for changing drainage when moving the toilet mainly include using a toilet offset flange, same-floor drainage modification, inter-floor drainage modification, and converting floor drainage to wall drainage. The appropriate method should be selected based on the actual situation, and relevant precautions should be taken.

Using a toilet offset flange: This is suitable for short-distance (within 100mm - 350mm, preferably not exceeding 400mm) relocation. You need to purchase a ready-made offset flange, chisel out 20 - 40mm of the floor slab, embed the offset flange and connect it to the original toilet pipe and the new position. Then, pour the floor, apply waterproofing, and finally lay tiles. If the relocation distance exceeds 300mm, create a slope of more than 3% at the embedded offset flange to facilitate drainage and prevent sewage accumulation.

Same-floor drainage modification:

• Floor slab lowering: If the bathroom's building structure already has a lowered floor (with the floor recessed by 250mm - 350mm), you can freely arrange the toilet and other drainage outlets. During the modification, it is advisable to use a sanitary tee as its design reduces sewage accumulation in the pipes and lowers the risk of blockages.
• Floor slab raising: Build a platform 180 - 200mm high using lightweight blocks, embed the toilet waste pipe (about 110mm in diameter), and then lay floor tiles. This method allows for long-distance relocation but involves a large amount of work. Moreover, for the elderly, the higher platform may cause inconvenience and increase the risk of falls.

Inter-floor drainage modification:

• Modifying the drainage on the ceiling below: You need to negotiate with the neighbor below and create a new drainage hole on their ceiling. There is no limit to the relocation distance. However, during the modification, ensure proper waterproofing to prevent leaks from affecting the neighbor's life below. Also, install a trap to prevent odors.
• Converting to wall drainage: Embed the water tank in the wall using a steel structure and hang the toilet on the steel structure. This modification method allows for a large relocation distance, has an aesthetically pleasing appearance, and is easy to clean. However, it requires the toilet to be close to the pipes, and the installation process is relatively cumbersome.

Converting floor drainage to wall drainage: If the toilet needs to be moved about two meters to the right, you can connect a 110mm pipe from the floor-drained toilet and extend it to the right at a 3% slope for connection.

Precautions: Whether a siphon toilet can be used after relocation depends on whether the layout of the drainage pipes is reasonable, considering factors such as pipe diameter, slope, elbows, and ventilation, rather than just the relocation distance. If the relocation distance is too long or there are too many elbows, it may disrupt the siphon conditions and result in weak drainage.