I have what I believe to be "black mould" in the silicon section behind my kitchen sink; from what I have read lots of moulds / mildews can be black, but the more dangerous one (Stachybotrys chartarum) I believe can only continue to grow in areas that are constantly wet as it needs constant moisture - because this area can be constantly wet perhaps that is what it is?

Here is a picture:

enter image description here

My question is - I have read that Vinegar can kill most mould (82%) and is far better than something like bleach and stuff like Tea Tree Oil may be even better - but my question is, assuming the vinegar/tea tree oil kills it, can I just spray it with Vinegar / Tea Tree Oil (perhaps a combination spray) and it will kill it and it will no longer be producing spores or does it need to be "removed" as well by scrubbing it out?

Yes, it would preferable to not have it there, but scrubbing it out provides more health hazards by agitating it more which may lead to a lot of spores going into the air, not to mention the cleanup of all the "gunk".

  • Is that really grout, or is it silicon?
    – Erik
    Commented Nov 11, 2019 at 12:40
  • @Erik I have no idea to be honest haha
    – Brett
    Commented Nov 11, 2019 at 13:28
  • Grout is the stony stuff you have between the tiles, silikon is that shiny, flexible stuff mostly used at corners, which get wet very often (e.g. along a bath/shower tub). If the mold has creeped behind the silicon, you have to remove it, scrub the area, then re-apply.
    – Erik
    Commented Nov 11, 2019 at 13:41
  • I just had a look and yes, it appears to be silicon. It's a rental house as well.
    – Brett
    Commented Nov 11, 2019 at 14:01
  • Depending on how you feel up to the task, how your landlord handles such cases and if there are other joint which need redoing, either ask the landlord to send a professional, or redo the silicon yourself.
    – Erik
    Commented Nov 11, 2019 at 14:08

1 Answer 1


I think you should remove all the silicone then use a bit of bleach to clean the area well to kill any remaining mold. Let it dry thoroughly and then put a new bead of silicone there.

You mention this is a rental property. You may want to talk with the landlord about this. If there is mold, then water is getting behind the silicone and potentially causing further damage. The owner should take it upon themselves to fix this.

  • 1
    mix bleach and water at 10:1. 10 parts water, 1 part household chlorine bleach. Spray before you start disturbing things and while you are disturbing things.
    – Tim Nevins
    Commented Nov 11, 2019 at 14:52
  • Thanks for the answer, but bleach is a bad idea to try and kill mold, particularly on porous surfaces. From my understanding it can kill live mold, but it won't kill the spores, but even worse, it can make the situation worse when it grows back, and it can actually feed the mold. Not only that, but it's much harsher to human health to breathe in than something like Vinegar (or a range of other options).
    – Brett
    Commented Nov 11, 2019 at 16:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.