How To Remove Mold From Shower Caulking?

Discussion in 'Plumbers' Talk' started by CaulkHero, Apr 22, 2022.

  1. CaulkHero

    CaulkHero New Member

    Having a tough time getting all the mould off of the shower caulking, any tips?
  2. Severntrent

    Severntrent Screwfix Select

    Get some cloths or wet wipe type of thing, soak in Domestos and place/ press over mould, leave 24 hrs and rinse off
    Jord86 and WillyEckerslike like this.
  3. CaulkHero

    CaulkHero New Member

    I've been pouring bleach over it, tried vinegar, stain removers, and was considering scraping it off with a razor blade but I'll try your suggestion first, thanks.
  4. MRY

    MRY Screwfix Select

    Is the mounld on the caulking, between it and whatever it's supposed to be sealing, of has it actually got into caulk itself (rather than just growing on it)? If it's in ut or under it, you will probably be better off replacing it...
  5. Nexial

    Nexial Member

    Scrape it off an put on Dow 785
  6. WillyEckerslike

    WillyEckerslike Screwfix Select

    The bleach trick is definitely worth a try. We've had good success with it soaked into kitchen roll.
    vrDrew63 likes this.
  7. DIYDave.

    DIYDave. Screwfix Select

    Depends on the quality of the silicone (it won’t be caulk) used in the first place, how long the mould has been there for and if it’s just on the surface or, more than likely, it’s got its claws actually into the silicone

    Can’t always be removed, whatever method you try, but obviously worth trying first

    If it doesn’t shift - then it’s cutting out the silicone, fully cleaning the areas, replace with quality silicone - job done and maintain it with a regular spray of Dettol Mould Remover (think that’s what it’s called)

    Bleach based bathroom spray, loads out there but find this one really works as long as the mould hasn’t taken root
  8. vrDrew63

    vrDrew63 Active Member

    Absolutely can second this. Saw this handy video from Skillbuilder on getting rid of mould on silicone caulk in a shower. Followed Roger's directions, let it sit for ± 20 hours, and the mould was absolutely gone, with zero scrubbing or hassles. Roger suggested using loo roll, which has the advantage of being readily to hand in most bathrooms.
  9. Truckcab79

    Truckcab79 Screwfix Select

    DIYDAVE is spot on. Dettol mould and mildew is the best there is. It just works. If that doesn’t shift it in one application then cut out and replace. Actually far quicker in the long run than messing about with variations of bleach and kitchen roll.
  10. DIYDave.

    DIYDave. Screwfix Select

    Cheers mate …. At last someone agrees with my suggestion :)

    What a fantastic start to the weekend ,,,,, and things can only get better from here onwards

    Have a great one yourself Truck ..
  11. Severntrent

    Severntrent Screwfix Select

    A few minutes to soak and drape on mouldy areas and then just a question of waiting and see but if Dettol is as good as you say it is spending hours cutting out, cleaning up and re grouting won't even come into it in the long run. Hopefully the OP will give us some feedback back and he will have a go with Dettol 1st
  12. Astramax

    Astramax Super Member

    I don't agree?

    Use the best ....HG Mould Spray
  13. Truckcab79

    Truckcab79 Screwfix Select

    To be fair the ‘best’ is sodium hypochlorite sold at 14-15%. Most of the sprays will only be 4-5%. But that’s more than strong enough. HG works well. Not much in it compared to Dettol. Just Dettol is more readily available generally.

    I’ve just finished head to toe redecoration of a two bedroom rental flat for a client. Every window reveal covered in mould, and deep into the plaster, caulk and silicone. Bathroom even worse as you can imagine. Dettol (or HG) spray gets rid of about 70% of it in minutes. The rest will never shift. In my case it was cut it all out or for the plaster Zinsser stain block and then paint.

    Don’t waste your time on anything that takes more than a couple of minutes. It’s not shifting.
  14. Severntrent

    Severntrent Screwfix Select

    Disagree, mine took 24hrs and it disappeared, but time will tell
  15. CaulkHero

    CaulkHero New Member

    In the end I followed suggestion 6 from this blog post and used Borax as literally nothing else worked, and it did the trick...
  16. burmese

    burmese New Member

    I've tried Dettol, no luck and HG Mould Spray doesn't work. I've had it for ages and asked the company if it expires. I didn't get a straight answer. They just said it doesn't get to mould underneath the silicone. Has anyone experienced it going off? I'll have to try the bleach soaked paper method. There's too many corner areas to re-silicone and I can't match up the beige silicone that was used around 10 years ago.
  17. vrDrew63

    vrDrew63 Active Member

    The bleach-soaked paper method is, IMHO, the best bet for stubborn black mould spots on shower silicone. It's cheap, easy, and relatively low effort.

    Get the "thick" bleach. (It's usually 99p or so in most supermarkets, so not a huge investment.) Wear rubber gloves and make sure you don't breathe the fumes. Kitchen roll works best, but loo roll will do. Wait until the shower isn't going to be used for 6-8 hours, preferably overnight, and apply a "poultice" of bleach-soaked paper over any black spots. Really soak the stuff. You want the bleach to remain in contact with the mould for as long as possible and not dry out or evaporate away too quickly.

    After letting it sit several hours, remove the (hopefully still wet) paper, and chances are the discolouration will be gone. Rinse well with water to remove any remaining bleach.

    To prevent mould coming back? 1) Make sure extractor fan runs when bathroom is used (set timer for appropriate duration); 2) open window unless freezing outside; 3) use a squeegee to to get water off tiled walls and surrounds after every shower; 4) wipe down walls with sponge-cloth daily; and 5) spritz entire area with daily shower spray. Keeping the shower clean and dry removes any home for mould to grow in. And getting the humidity out of the bathroom lessens the chances for other problems - like failing paint or rusty radiators.

    I know the "prevention" regime sounds like a hassle, but if you get in the habit of doing it every day your shower and bath stay amazingly shiny and fresh. My girlfriend recently commented that my upstairs bathroom was "immaculate" - which I think is possibly the first time in the history of mankind that such a comment has been made by a female.

    I will also note: I happen to have a household water softener. I know there are people who consider such contraptions to be the Devil's own handiwork. But mine does do a pretty darn good job of keeping soap scum and calcium deposits off my shower and bath. And soap scum and calcium deposits also give water an extra rough surface to cling to and encourage mould growth. Take that observation for what it's worth.
    Last edited: Jun 10, 2022
    Astramax likes this.

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