How to fix gap between tiles and shower base?

fan8956

Hi, thanks in advance for your help!

I’ve noticed a crack between the silicone and the bottom edge in my bathroom, and ants are coming through the gap. I have a few questions:

• What silicone product would you recommend for sealing this area?

• Should I remove the old silicone completely before applying new sealant, or is it okay to clean the surface and just fill the gap?

• If removal is necessary, how much should I take out—just the affected corner (around 5cm x 5cm), or more?

• What tools are best for removing old silicone? I tried using a knife, but it’s proving difficult.

• How urgent is this issue? When I washed the wall with water, some kind of black sand came out. 

• Regarding the ants: I’ve read that there’s usually a waterproof layer behind the tiles. If ants are getting through, could this indicate a bigger issue behind the wall? I asked AI earlier and was told that a small hole from ants shouldn’t be a major concern, and resealing the silicone should be enough. But I want to double check with the professionals here.

EricL

Hello @fan8956 

Please allow me to answer your questions in sequence:

• I suggest using Selleys 300g White Wet Area Waterproof Silicone Sealant. It's designed for sealing wet areas such shower screens, baths, spas, sinks and plumbing fixtures, it has a built-in fungicidal protector to stop the growth of black mould and fungus.
   
• The old silicone must be totally removed before applying the new silicone on the bath.
   
• It would be best to remove all of the silicone surrounding the edge of the bath. It is not recommended to mix old and new silicone sealers.
   
• I suggest using the Trojan Safety Scraper With 5 Blades to strip the old silicone off the wall and bath, please take extra care on the bath to prevent scratching its surface.
   
• It would be best to do it as soon as possible. The black sand is from the nest of the ants, I suggest using an ant spray in the gap before you seal it with the silicone sealer.
   
• It's highly probable that the ants got through a gap, but it is not yet enough to warrant a full-blown re-tiling job. Just keep an eye on walls around the outside of the bath for water leaks. My best advice is to treat the ant infestation before you seal the gap.

Here is a handy step-by-step guide: How To Silicone Seal A Bath 

Please remember to wear personal protection such as gloves, goggles and a mask when working on your repair project.

If you need further assistance, please let us know.

Eric