Is the leakage of the ventilation wall in the bathroom due to the lack of waterproofing?

Not necessarily, I did deal with a problem today, which has nothing to do with the upstairs (or can't be solved from the upstairs). Mainly the water pipe problem. >>>More

Not necessarily! The leakage of the downstairs bathroom may be due to the fact that the waterproof layer downstairs is not done, and when the water accumulates a lot, it will continue to seep water to the top! Hope it helps!

The downstairs bathroom is leaking, and it should only be topped. >>>More

In fact, the water leakage downstairs is not necessarily caused by the water leakage upstairs, but other reasons can also cause water leakage. For example, first check whether the upstairs kitchen and bathroom are waterproof, and whether there is any accumulation of water on a daily basis. >>>More

The leakage on the roof downstairs must be the cause above....There is no water leakage on the top, how can there be water leakage on the ceiling below.