How to Remove and Replace Silicone Properly
By Wall Boulevard
Silicone is the part of a wet area that needs replacing on a schedule. It wears out, it discolours, and it is far more susceptible to mould than grout is. In a shower, around a bath, behind a kitchen sink or in a laundry, that bead is doing real water protection work, so a tired one is not just a cosmetic problem.
The first rule is that you cannot run new silicone over old. It will not bond, and you will be back doing it again within months. All of the existing sealant has to come out.
Get your gear together before you start: a sealant remover, a remover tool, a knife or scraper, a cartridge gun, a sealant smoothing tool, mould remover, methylated spirits, gloves and a clean cloth. For the silicone itself, Mapesil AC and Mapesil LM both do the job. Read the directions on whatever product you buy, because cure times and application notes vary.
Apply the sealant remover as directed on the packaging, then scrape the old bead out with the remover tool or a knife. The pointed tip on a remover tool is designed to get into the joint between tiles. Go carefully with a knife: in a shower you can cut straight through the waterproof membrane behind the tile, and that turns a small job into a very large one.
Gloves on for the next part. If mould has got into what is left of the sealant, treat it with mould remover, then rinse it away thoroughly. Let the area dry completely, because new silicone will not adhere to a damp or contaminated surface.
Degrease the joint with methylated spirits on a clean cloth. Load the cartridge into the gun and run the bead slowly and steadily from one end to the other, keeping the pressure consistent so you do not leave gaps. It will look messy at this stage, which is fine.
Run the sealant smoother along the bead with gentle, even pressure. A finger will do it, but the tool gives a cleaner line and a more professional finish. Then leave it alone.
Cure time is the step people rush. Check the product directions and give it 24 hours before any water touches it, so the adhesion has a chance to set properly. Get that wrong and the bead will fail early no matter how well the rest of the job went.
Talk it through with us at either store. 19 Mantell Street, Coburg North VIC 3058, (03) 8683 6514. 1/8 Lakewood Blvd, Carrum Downs VIC 3201, (03) 9005 5027.
