Hello. I'm trying to fix worn out grout above my bathroom (white porcelain) tub. I dug out much of the old grout, and 1/2 of the botom tiles came out in the process. This row of tiles is cut to only about 3/4" high, and 4" wide. The spacing between tiles is 1/16", and 1/4"-1/2" between the tiles and the tub. Behind some tiles is a bit of the backing wood wall, and only empty space behind others because the backing board ends short. In some places I could glue in thin 3/16" strips of wood onto the riser beams behind. I repositioned the tiles by gobbing in 'SimpleFix Pre-mixed Adhesive & Grout, for grout joints 1/16" to 3/8" ' behind the tiles on the tub, the bit of backing available, and between the new tile and it's neighbors, but not filling in all the way so I can now do a surface grout after it set (I thought it might shrink and not work if I filled in, adhered the tiles, and grouted all the way in one step.)
Now I need to grout or caulk the positioned tiles and am not sure what to do. I read that regular grout will crack on the tub/tile gap because of motion when the weight of water/bather enter the tub.
My questions are:
1. What is appropriate to use in this tub/tile gap? I read that normal grout wasn't flexible enough or doesn't bond the tub well enough to use at the tub/tile joint. The "adhesive grout" has an "acrylic copolymer"; will it be good for this purpose? If I should use caulk, as I'm starting to think, what kind? The manufacturer of the silicone grout I have says it's not good for gaps deeper than 1/4".
2. The "Adhesive & Grout" stuff is sandy, will I damage the porcelain (I think) tub, or the ceramic (I think) tiles? It does seem OK so far. It seems sandy. I read contradictory things on whether sanded grout is OK for 1/16" gaps, and this adhesive/grout feels sandy.
3. How about the joint where 2 walls come together? The existing had silicone behind caulk. What should I use?
Thank you. Any help is apprecitated.