How to Remove Black Mold from Silicone Sealant

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Silicon sealant is pressed from a tube and smeared next to walls along sinks and showers to prevent water leaking behind the fittings. Because of its rubbery surface, it enables mold to settle easily and engross it. Mould also thrives in damp and warm environs. That’s why you’ll find it in kitchen sinks and bathrooms.

When mold builds up on the sealant it becomes very hard to clean, especially if it’s ignored for a long time. Even with the best chemical removers, it may be impossible to get rid of it. In other cases, moulds can still develop on the sealant even though you clean regularly. Black mold in is not only hideous but risky to your health as well.

Being conversant with the correct cleaning procedure and proper tools can save you a lot of money, time, and worries.

This guide shows you the best way to remove black mold from silicon sealant.

How Do You Remove Mould from Silicon

Use Home Remedies

Easy way to clean black mould mold from silicone mastic sealant caulking.

Some home remedies can help you get rid of mold from the silicon sealant. Always stock your home with everyday ingredients such as vinegar, baking soda, and a versatile cleaner.

You will need the following;

  • Baking soda
  • Bleach
  • Paintbrush
  • White vinegar
  • Borax Gloves
  • Plastic wrap
  • Spray bottle
  • Respirator (or face mask)

The gloves and respirators are for protecting you from chemicals and fumes from some toxic cleaning items. You also need to get clothes that can tolerate chemical and color spattering from the cleaning process.

Then follow the below easy steps:

  1. Add about 2-3 tsp. Of baking soda to 1 cup of bleach or as much as you want to create a paste.
  2. Scoop out a small amount of the paste using a piece of cloth.
  3. With a thick enough layer of the paste over the mold, start rubbing it. Have your gloves on at all times.
  4. Give the paste 5 minutes to settle on the mold. Cover it with the plastic wrap. This is meant to keep the moisture within the paste to let work.
  5. Scrub the paste from the sealant using a hand brush with tough bristles. Do as quickly as the bleach breaks the bristles of the brush.
  6. Use cool water and a sponge to rinse the sealant.
  7. In case some stains persist, repeat the procedure 4-6 times until the mold is completely gone.
  8. Rinse and dry the area with a clean, dry cloth or towel.

Some key points to note.

  •  You can also use vinegar alone and let it sit on the mold for 30 minutes before being rinsed off.
  • You can also use a dilute mixture of Borax. Mix 204 grams of borax powder in 3.8 litres of water and spray it on the affected areas then leave it. This doesn’t need rinsing, and it prevents future mold growth on the silicon surface.
  • Use diluted bleach. Mix using 1:10 ration of bleach to the water. This will give you a solution to spray and leave on the moldy areas of the silicone. You can either spray the bleach or put wet cotton wool with bleach on the affected areas.


  • Bleach can weaken the grout and tiles, or even cause it to fade.
  • Never mix bleach and vinegar; it creates poisonous chlorine gas.

Using Commercial Mold Cleaning Products

Most of these commercial mold cleaning products use bleach as an active component. The bleach is usually listed as sodium hypochlorite. Nonetheless, the bleach concentration in these ‘mould killer’ products is hardly 5%. This is a very small percentage to eradicate the mold.

Also, bleach has a short shelf-life and loses potency quite fast, so if the products have been on the shelves for a longer period, chances are they are not effective.

All in all, you need to do your due diligence before purchasing any commercial product. Check customer reviews and even consult professional cleaners on the best product.

Seek Professional Cleaners

If mold covers a larger area of your home (approximately over 1sqm) and appears to be dense, then it’s probably the best idea to call for the experts.

Charges for professional help vary. The expert will first check the place and find the source of the mold then propose the best way to remove the mold. The total cost depends mainly on the level of damage and the size of the area affected.

Mold removal experts need to be certified, have the right equipment, and fit.

How to Prevent Mould from Coming Back

Use the following tips to prevent molds from growing back into your home.

  1. Repair any leaking roof or broken pipes as they act as access points for moisture.
  2. Set up a good fan in the bathroom and inhibit moisture build-up on surfaces. Use a dry towel or squeegee on your tiles and floors immediately after bathing.
  3. Always ventilate your home. Poor ventilation is among the key reasons homes become at risk of mold growth. Humidity builds up when air is not moving. Get a dehumidifier as an option if you can’t ventilate.
  4. Ensure clothes are completely dried outside, not indoors, specifically if there is scarce ventilation.
  5. Clean your home regularly.

Prevention will save you from dealing with the tough mold, and save the money you could have paid the cleaners.


You can effectively remove black mold from silicon sealants with home remedies or commercial products. You can also practise prevention measures to save yourself some time and money. If the above remedies don’t work, the mold may have affected the parts beneath the silicone. Once the mold gets its hold here, eradicating it is almost impossible. When mold breeds, it grows roots, which penetrate the grout or silicone. You can only clean the surfaces of the silicon but not underneath it. This will make you change the silicone with a new sealant. Because silicon is not used for covering a large area it should be easier to remove and it may take less time than cleaning.

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Joe McGuinty
I’ve been working with floors for over 12 years. I started as a flooring contractor, primarily in materials selection. Then, I switched careers into accounting, so my wife and I began buying, renovating, and re-selling homes on the side. You’d be surprised how much value you can add to a home simply by adding new floors.

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