I just bought a rental property and one of the tenants bathrooms seems to have a mold issue. In the shower, around the toilet, and around the perimeter of the room there seems to be mold/dirt build up. I've added pictures below for context.

There is a fan in the center of the room and the motor was replaced in it a few months back, however, I have not verified how well it actually ventilates. The walls are made of a plastic paneling made to look like ceramic tiles.

My current explanation for the problem is either the fan is not ventilating enough or the material used within the shower and walls is not moisture resistant, however, I'm inexperienced in this area, so I'm not sure how much a fan will help with mold and the material seems like it should be moisture resistant.

As for the dirt/mold in the perimeter of the room and around the toilet, I have no idea how that would form.

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1 Answer 1


First thing you want to do is verify that the fan is working. If there is an attic, you need to get up there and check the venting to the outside. If no attic, then remove the fan so you can stick your head up there and see what's going on with the vents. Poor ventilation is a major cause of mold and mildew. All my bathroom vents have 60 minute timer switches.

Next, mix 1 part bleach and two parts water in a spray bottle and spray down the whole bathroom. I don't usually use bleach, I use vinegar because it soaks into porous materials and bleach doesn't. In this case I'd use the bleach: spray, scrub, wipe down, spray, scrub, wipe down. Once everything is clean, wipe the floor down with vinegar. It will soak into the grout and prevent the return of mold. Keep in mind that the walls are probably not made of that plastic. The plastic is a wall covering and there could be mold behind it. If any of the plastic is loose, pull it out and check for mold behind it.

Last but not least, think about replacing all the caulk in the bathroom. Good luck.

  • Thanks for the advise, but how do I prevent it? Does mold form due to poor ventilation? Dec 14, 2019 at 20:30
  • 2
    The mold forms when it stays damp or wet for long periods of time. Even worse if it is a warm and damp environment. This is the reason the fan is so important that it works well, vents fully to the outdoors and is used properly when the bathroom is in that warm damp environment.
    – Michael Karas
    Dec 14, 2019 at 20:34
  • the cause could be a water plumbing problem, but check that the vent is working first.
    – Jasen
    Dec 14, 2019 at 22:07
  • Mold needs dampness and organic matter. So dry and clean. Hard to achieve in a normal bathroom, but keep at it.
    – DaveM
    Dec 15, 2019 at 1:15

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