For sunken toilet backfilling with same-layer drainage, waterproofing treatment before toilet backfilling, selection of toilet backfill materials, toilet backfill support and ground practice. Only by completing these three aspects can we ensure the quality of our bathroom backfill. Set up caisson internal drainage pipes. That being said, the first thing we need to do is drain the drain pipe in a sunken toilet. These mainly include the floor drain drainage in our bathroom, the drainage of the washbasin, and the drainage of the toilet. These pipes must be connected to drainage risers. Moreover, if conditions permit, the bottom leakage of the second drainage should be carried out. No further work can be done until these pipelines are completed.

Complete the waterproofing of the inner wall of the bathroom caisson and the bottom of the caisson. In other words, we need to waterproof the bathroom bedside table after the pipes in the bathroom are completed. The usual method is to use polymer, cement, and mortar waterproof coatings, and waterproof coatings are not allowed to be painted more than three times. Make sure our caisson walls and floor have a uniform, dense waterproof coating. After the drainage pipes and waterproofing of the bathroom are completed, we will also conduct a wastewater experiment on Kaisen at this time. In this case, it is generally necessary to fill the caisson with water and wait 72 hours to see if there is any leakage. If there is no leakage, it can be considered qualified and the next stage of backfilling work can be prepared. If there is a leak, it should be waterproofed again until the closed water test is passed.

When the developer came out of the house, the bathroom was waterproofed once. We drained the water, turned it off, and tested the integrity of the waterproofing (most of the renovations were done alone for safety, so there is no water seepage downstairs). At this time, if the backfill material is sharp, the waterproof layer will rupture when the gravity tears underneath when pouring the backfill material. If there is a leakage problem in the drainage pipe later, the leakage will be transferred from the waterproof leakage to the top of the downstairs toilet, causing property damage to both parties.

Carbon residue has good absorbency, small size, easy to fill gaps, light weight, certain load-bearing performance, and convenient construction. It is a combustion waste and is an economical material that can be used as toilet backfill to reduce garbage piles. However, due to environmental protection controls, carbon residue is becoming less and less. Mainly indoor wall demolition or other construction waste materials. The characteristics of this kind of backfill material are that it is easy to construct and requires no cost. However, the material has obvious edges and corners, which can easily scratch the waterproof layer below. It will leave a large gap after backfilling, causing poor charging and heavy construction waste, which is a negative impact on the internal force of the floor. In the test, backfilling of building materials is generally not allowed.