I have a marble piece, and on top of that I have a sliding glass door (one sliding and one fixed).
The issue is that between the floor (marble) and the fixed glass panel there is a gap of 1/4 inch where water is escaping to the other side of the shower.
I thought about the following solutions in order of effectiveness:
Silicone: don't want to use, because it's too hard to remove later in case of any maintenance (will get stuck/leave residue on glass and marble).
Flashing/vinyl seal: would be my best option for now because it allows easy removal if needed, but in my opinion it looks ugly (plastic and marble together...).
Any other options I could consider that will not interfere with the current look, and will be effective and not so hard to remove later when/if needed?
Clear silicone is very very very easy to take off marble and glass. There is no residue after hitting it with a glass scraper and some mineral spirits - a big shower is maybe 15 minutes.
For application on something like 1/4" I would put a first coat down that should fill most of the gap. Then come by about 1-3 hours later (depending on air flow and temperature of room) - you want the first coat to harden a little but not be set - and put a finishing coat that looks good and fills the rest of the gap. Do it right.
(There are also some edging strips that you could use. You would effectively have to use glue - silicone - to install them and they would be a PITA to remove. But the big issue is this shouldn't have been installed with a 1/4" gap)
This is a 36 x 1/2 inch strip of marble. Get something to match the marble you have. You would set it in the shower so it occludes the opening. If 36 inches is too long ask them to cut it down to size at Home Depot or tile store. The issue is with the fixed piece of glass and so it does not move. Neither does the strip of marble. It would be easy to clean because it is not attached; you can pick it up and scrub it, and behind it / under it too.
Plus I like the installation. Set it down, and done.
If you want to get fancy you could caulk it in place, but then you would have to buy caulk.
Based on @Ack's recommendation, I found a silicone tape which I think has best the both words: protection of silicone but easier to remove/replace when necessary.
I installed in the wet side and I'm not sure how the tape will hold. If necessary I'll install it in the dry side so tape doesn't come in contact with water (but silicone will still prevent water from travelling to another side).