Shower corner has grout covered in caulk

Question

We just moved into a newly flipped house, and one thing we've noticed in the showers are that the vertical corners are filled with grout, and then covered by caulk. I've always been told that any tile joints that change planes should be caulk, not grout, so that the grout won't crack as things shift over time.

I was able to notice because the caulk doesn't cover the grout very well, so I probably should fix that regardless. Can I just put a new layer of caulk over what is already there, or do I need to remove the previous layer first? Do I also need to remove the grout and replace the whole joint with caulk?

To address some questions in comments: The whole bathroom is less than 6 months old, so it's all in good condition at this point. I ask my question because I understand this to be bad practice and so it should be fixed to prevent issues in the future (mold, cracks, leaks, etc). If people don't think this is a problem then I'm happy to leave it as-is.

Here's a close-up of the worst section. The grout is about 0.25" wide.

Answer 1

The grout, assuming the rest of the shower was installed properly, isn't the last line of water defense so it's probably fine to leave as is. Grout is permeable anyway so it wouldn't be a good line of defense anyway. That being said, you can leave it as is.

If you want to recaulk it then I would definitely remove the grout as the new caulk will not adhere well without more room. They sell little hand-held grout removers at the home improvement stores and, in my experience, they're not going to do the brunt of the job. You'll need an electric oscillating tool to get it done. You'll also need ear protection because the echo in a shower will make your ears ring for a day (I speak from experience). For obvious reasons you'll also need a mask. Your electric tool will likely leave little bits of grout that you'll follow up with the manual tool.

Answer 2

It looks like a good urethane caulk was used, but that might just be latex. It wouldn't be a concern except for the poor quality of the bead.

I'd use a razor blade to cut (scrape) the existing caulk out, then install a similar bead of color-matching urethane, but with continuous coverage. Since this isn't pure silicone you won't need to get the old caulk completely removed. Just get a clean, smooth surface. Be aware that urethane is extremely sticky and doesn't come off skin or clothing.

Cut the tip of your tube very small, at an angle, and clip the point off the cut outside the opening. A full chisel tip will scrape away your bead, where a clipped tip will just flatten it for you.

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