I recently built a shower pan, and everything in the shower is fine, except that my grout on the floor seems to not seal well. I have regrouted approximately 3 times in certain areas, which I suspect is because there are slight puddles in these areas, although they are not substantial (less than one centimeter squared). Are there any types of grout that are more resistant to lifting out of the grout lines than others?

I don't know what is wrong except maybe the flex on the floor is loosin'in up the grout lines.
Most tile stores have a sanded calk that matches the grout color and use that.
Can't match the color, then I guess pick a nice color that will still look good.

That's awesome; I was hoing for an answer like that, as I live in quite a small community where little will help. Thank you!

Grout is not impervious to water All grout needs to be sealed in bathrooms Ita a clear sealer that comes in a little squeez bottle with a small brush on the end of the bottle. Two types of grout sanded and unsanded. If for the difference of the grout width. Moisture will get under grout and that can also lift grout kepdog has a point check floor stability and then go from there. Grout in all bathrooms and kitchens needs Sealed. Good luck