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How to clean mould underneath silicon?

Hi guys

recently renovated bathroom and I am starting to see dark/mouldy thing under the silicon. This is the best I could get using dishwashing liquid washer liquid and I am worried if I will peel off the silicon if I scrub harder. Is there any product to clean such stubborn dirt? It looks like to me that there has been seepage but again, if seepage was there I would be able to clean with water jet, but does not look like it.

Thank you.

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JacobZ

Hi @Sugar,

That's definitely mould you are looking at. Once it gets in underneath the silicone, it can be tricky to deal with without removing and replacing the silicone.

Give a mould killer like this Selleys Rapid Mould Killer Remover a try. Apply it, let it sit for 30 seconds, then give it a scrub with a scrubbing brush, then wash it with clean water.

Unfortunately, if it has penetrated inside the silicone, which seems likely, then it might call for the silicone to be cut out and replaced. If you do this, then make sure to spray beneath the silicone with mould killer and scrub it, before applying new silicone as the spores can sit dormant in this gap waiting to reemerge.

Check out How To Apply Bathroom Sealant for a guide on how to reapply silicone.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

Sugar

Thanks @JacobZ

I am going to tell this to my renovator who did this. Hopefully he will understand this and fixes it, althought it is 7-8 months already. However, I need to be prepare for "no" answer.

In worst case scenario ( I do not get help), how hard is it going to be to cut the silicone ( I guess not that hard,but would like to take every precautions) ?

Would you think that there will be water ingression even beyound those silicons as this moulds are created only because of that ? I am asking that because the main reason for renovating this bathroom was because one of the tiles had grouting cracked and it was leaking to another room. That was the story before to get this bathroom renovated. However, the leakage was through the wall tiles. It was found that (according to the renovator), there was no waterproofing done back then. However, Water proofing has been done this time.

Red is where we had issue before.

Green is where most of the moulding is.

If this is easy enough job (to remove, to clean and to apply new silicon, and which I have done fair bit of job around kitchen areas before), I wouldn't even bother to call my renovator as he lives one hour away and makes plenty excuses of distance and this and that :(. But, I will do the call if you think that's very very critical task to look beautiful.

Thanks for reading so far.

JacobZ

Hi @Sugar,

If the waterproofing was done correctly, then water passing beneath the silicone isn't a huge cause for concern as it will hit the waterproofing membrane and slowly flow towards the drain. It's not ideal for water to get beneath the tiles, but it is also not the end of the world if the membrane is sound.

Cutting out and replacing silicone is relatively easy, so I don't think you'll really need to call your renovator in.

To remove the old silicone, run a utility knife down each side of the gap to break the silicone's connection, then peel it away. Make sure you wear gloves and long protective clothing to reduce the risk of lacerations.

Once the silicone has been removed, make sure to apply some mould killer to the gaps and give them a scrub. You want to make sure there are no living mould spores beneath your new silicone, so it is certainly worth the small amount of effort.

Once clean and dry, you can follow How To Silicone a Gap and How To Apply Bathroom Sealant to reapply your silicone. Make sure to select one that is the same colour as the old to ensure consistency.

Apply the silicone, then wet it down and use a Silicone Scraper to strike off the excess and create a smooth bead. Keep plenty of paper towels or rags around for clean up as you go.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

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