Operating rules:
1. Before light backfilling, the caisson should be cleaned and the inlet and outlet pipes should be fixed to avoid touching the pipes during backfilling.
2. The recommended ratio of ceramsite to cement is 5: 1.
3. The bottom of the box should be made of ceramsite as the secondary drainage channel, which is generally discharged to the secondary drainage outlet according to the bottom edge or middle of the box.
4. When the caisson is backfilled for about 4/5, it shall be leveled with cement mortar for about 30mm-60mm and compacted. If you put the bathtub, you must add φ6 reinforcement to make it 20cm square.
5. Finally, add barbed wire and use 1: 3 as cement mortar for leveling, and slope for waterproof bottom layer.
Second, the quality requirements:
1. The pipeline shall be firmly fixed.
2. The proportion of ceramsite and cement should be accurate, the water should be accurate, and the mixture should be stirred evenly.
3. The joints of barbed wire should overlap 100 mm or more.
Third, matters needing attention:
1. Compact but don't step on the pipe.
2. The backfill should be dense.
3. The iron wire and cement mortar should form a collective, and the cement mortar should carefully find the usual slope.
4. Pay attention to the elevation of the bathroom floor finish, and avoid being higher than the corridor or hall floor.
Link 1: Make waterproof coating twice. Waterproof coating must be made together with the wall, and the height of the wall should be more than 40 cm above the upper edge of the open caisson. Ensure that the upper water will not spread around and can only be discharged to the floor drain.
Link 2: Red bricks or concrete are used as isolation overhead, and the caisson is divided into several grids of about 400*400. Many people don't do this step. In fact, this is a very important link. With such load-bearing isolation, the concrete layer above will not fall off. Otherwise, the bathroom floor will sink, crack and leak in a few years.
Link 3: Fill ceramsite or fly ash. Fill with moisture-proof ceramsite and grid, don't press it too tightly, be generous, because it doesn't bear load, but only absorbs moisture.
Link 4: Laying steel bars. A 200mm*200mm square steel mesh composed of steel bars with a diameter of 5mm is laid above the grid to ensure the firmness and uniform stress of the concrete layer.
Link 5: Concrete reverse layer, leveling with 40mm thick C25 fine stone concrete. This layer should be made into a groove, waterproof coating should be done twice, and waterproof layer should be done together with the wall. After the waterproof layer is dry, it should be protected with plain cement slurry to avoid scratches when laying floor tiles and sticking tiles. After the protective layer is dry, people can do the next tile laying.