I have water seeping from the grout where the wall of my shower meets the floor. (The tile is travertine, in case that's relevant). In the picture below, the shower hasn't been used in over 24 hours, and the rest is completely dry, except for two other similar spots on the grout.
I first noticed this about a year ago. I removed a large section of the old grout, and discovered a surprising (to me) amount of water, maybe 1/4" in the gap behind the grout. I let that completely dry, then re-grouted and applied sealer.
A few months later it re-appeared. Since then I've just been letting it dry and applying more sealer, but it is reappearing more and more frequently. I can also see hairline cracks in the new grout already - I'm assuming this is where most of the water is getting in.
My thought is to tear out the grout in the floor-wall joint and replace it with caulk. But I'm a bit concerned that if water still gets back there somehow, the caulk will seal it in and prevent me from noticing until it starts coming out somewhere worse.
Any advice on how I should deal with this?