I just finished up a second shower tiling project in my house. I was excited to see how much more smoothly my second tile job would go than my first. All was good until the final step of caulking the shower corners where the tiles meet. I decided to use a clear 100% silicone caulk because the corners looked good and I wanted to show them off.
The grout that the silicone has touched is now much darker than the rest of the shower.
I'm obviously disappointed that this happened in the last step of the process. I spent a lot of time planning things out and even spent the extra money on a high quality grout that does not need to be sealed (Laticrete Permacolor Select). I waited several days after grouting to apply the silicone.
I've now waited almost 48 hours and the discoloration is still present.
Has anyone experienced this before? Any recommendations on how to resolve?
I'm thinking about removing the caulk with a razor blade and purchasing a caulk from the grout manufacturer that matches the color of the grout. This would hide any possible staining that clear silicone caused, but I'm hoping I don't need to go this route. In the only other shower I tiled, I ended up having to remove the silicone and add a different color and I'm really hoping that I don't have to go through that again.
Best Answer
Generally speaking, any time you apply a glossy material over a matte material you get darkening. It's unfortunate that this was discovered now, but you do have options.
If you haven't yet sealed the grout, and plan to, see what that does for the situation. Some sealers won't change the color, but some will. Maybe it'll bring things closer to a match.
Otherwise you'll need to cut away the caulk, scrape off at least the surface of the grout (deeper is better for bonding), and re-grout those joints.
Clear silicone is great for many things, but color-matched caulk is better in this situation, and urethane is the best I've used in terms of grab and durability. Use as small a bead as possible (trim the nozzle to act as a tool and don't "finger" the bead out), and note that urethane does not come off what you put it on. Plan well, wear latex-type gloves and old clothes, and consider masking the tile outside the bead boundaries.