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.

Leak around pipe in concrete floor enter image description here

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.

Top view of pipe

  • This should be the responsibility of the landlord, not the tenant. If you think it is actually sewage waste water that is leaking, I would suggest getting the health department involved (if the landlord isn't amenable to making repairs).
    – Dave Nay
    Commented Jun 19, 2012 at 14:42
  • There's no landlord. We own the apartments. The leak is not sewage. It is water from the bathroom not from the pipe. Commented Jun 19, 2012 at 14:50
  • Ahhh...OK, just a terminology conflict then. I would commonly refer to an owned unit as a "condominium" and a leased unit as an apartment. What is the source of the water? Condensation? Kids splashing in the tub? As sharptooth states below, this is going to require the cooperation of your neighbor.
    – Dave Nay
    Commented Jun 19, 2012 at 14:53
  • Concrete is porous and acts like a sponge for water. Sealing it in one place will just cause the problem to move to another place. You have to fix this at the source of the leak.
    – BMitch
    Commented Jun 19, 2012 at 14:57
  • The guy upstairs is gonna hate that he has to rip up the tile and put in a new membrane properly. Had this in our house, had to rip out the old and install new floor - the membrane "can" be fixed/glued, but over time the patch will fail again. Commented Jun 22, 2012 at 20:00

4 Answers 4


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:


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.

  • +1 I'd say that the most likely problem is there's some minor crack somewhere near the drain hole (perhaps in the drain pipe), so it's the first thing to inspect before thinking of major repairs of the waterproof membrane.
    – sharptooth
    Commented Jun 20, 2012 at 5:33
  • 1
    The man from upstairs came today, while I was at work, and the wife let him in. He's filled around the pipe and cracks with cement. Don't know what he's done upstairs, probably the same cement round the drain, but I don't expect the repair to last more than a few days. Commented Jun 20, 2012 at 11:30

The real solution is to prevent water from escaping the pipe by finding and fixing the initial leakage. This will most likely include getting to the upstairs neighbor and kindly asking him to assist with this problem and if he doesn't want to assist bring that to the building management, authorities and the court.

It will be very problematic to seal the ceiling from your apartment. Concrete is not a sealant material - it will absorb and conduct water so water will eventually find its way to your apartment. So this would be just a waster of time.

  • The water is not escaping the pipe. It is going down the crack between the pipe and the concrete. Commented Jun 19, 2012 at 14:53
  • 2
    @Rincewind42: Sure, but water should be inside the pipe, not outside, so it clearly escaped the pipe at some point.
    – sharptooth
    Commented Jun 19, 2012 at 14:55
  • It's in a bathroom. Water goes on the floor during normal bathroom activities. Commented Jun 19, 2012 at 15:51
  • 1
    @Rincewind42: Amounts of water enough to leak to an underlying apartment should not go onto the floor normal bathroom activities. I'm sure there's some constant minor leak somewhere. Even if your neighbor likes water on the floor he should do the sealing on his floor, not you on yours.
    – sharptooth
    Commented Jun 19, 2012 at 15:55
  1. The tiles on the floor the grout the water leaks through there.
  2. The pipe also sweats, and sweating means water.
  3. The pipe is on the outside, rain and the water from roof can slide down the wall and wet the pipe, which leads inside.

Get the occupant upstairs to install a proper shower tray and pipe the water out from the shower drain straight through the pipes and out of the building. Concrete will always absorb then release water eventually but the shower tray and piping system (Without leaks)is waterproof. This is the cheapest and permanent solution.

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