I live in an apartment building. Each house has a bathroom with a concrete floor covered in tiles. In the corner of the floor is a drain with its pipe going all the way through. However, I have noticed water leaking into my roof space from the upstairs neighbor's bathroom. The leak seems to be through the join between the drain pipe and the concrete.
What is the best way to seal this floor so that the water will stop leaking through?
Edit: Added a view of the pipe from above as people are clearly miss understanding the situation.
Best Answer
From your last picture, the water proof membrane goes between the tile and concrete in the shower. It should be overlapped and sealed all the way to the drain so that any water that gets around any cracks or through the porous tile/grout can only escape through the drain. Once it reaches the concrete, it's too late. Like sharptooth says, this is something your neighbor needs to solve.
Edit: Here are a few sample waterproofing products that would be installed under the tile:
Aquashield
Shower Pan Liner
Note that it may be possible to add some silicone caulk around any gaps and apply some sealer on top of the tile and grout, but that solution would be prone to failure over time.