Sometimes, the only way to fix blackened and mouldy sealant is to completely remove and replace it. The sooner this is done after noticing the issue, the less likely the mould will cause long-term damage.
Gather your Equipment
Necessary equipment for sealant replacement includes a sharp knife and/or flathead screwdriver, a toothbrush or scourer, a caulking gun, masking tape, silicone sealant such as that at www.ct1.com/product_application/sealing-your-shower-tray-with-bt1-bathroom-sealant/, and a cloth or kitchen roll. Optional extras include a smoother tool, silicone removal gel, white vinegar and antibacterial wipes.
Remove Old Sealant
Scrape out the majority of the old sealant using the knife or screwdriver. You can then use the toothbrush or scourer to scrub the area. Be careful not to scratch the tiles or the bath/shower/basin.
Clean and Prepare the Area
Once all the sealant is removed, clean the area with a damp cloth. White vinegar may help remove any additional mould. Ensure the area is completely dry, then surround it with masking tape to provide a guiding straight edge and to prevent the sealant from spreading outside the target area.
Apply New Sealant
To prepare the gun, load with a cartridge of silicone sealant and trim the tip at a 45°angle, unless you have a self-applicator. Move the gun slowly and steadily along the line of the masking tape, again at an angle of 45°, ensuring an even application. If you do not have a smoothing tool, you can use your finger, with clingfilm or an antibacterial wipe to protect your skin.
Drying and Testing
Fill the bath, remove the masking tape and leave the sealant to cure according to the manufacturer’s instructions. This may take up to 24 hours. Do not use the bath or shower during this time. Once it is cured, you can check if the seal is effective by pouring water over it. Take steps to reduce incidents of mould in future.
The process of removing and replacing bathroom sealant if it becomes mouldy does not have to be complicated but is vital to protect your bathroom from rot, mould and other damage.