The joints between my shower and tile, and tub and tile are cracking and need freshening. My instinct would have been to use caulk but it looks like the original construction (my house is about 11 years old) used grout there.
What is the textbook method for this maintenance, grout or caulk?
You could basically do either. I’m assuming there’s been no significant settling and that the gap between tub and tile hasn’t grown substantially. My preference would be for grout, because I think it’ll look nicer. But it’s a bit more work, since you have to clean out the old joint, and it may be difficult to match the existing grout.
One other factor is that caulk is a lot more forgiving of expansion and contraction in the joint. It’s conceivably the case that your tub is not as firmly supported as it could be, and that when you fill it with water, it sags somewhat. In that case, you’d probably want caulk rather than grout.
Grout is used between the tiles. The tile should be attached to a backing of cement board, or a built up bed of cement in older homes. Grout is used because it is more durable than caulk and the tiles don’t move apart from one another. Be sure to remove the old grout so that the new stuff beds down between the tiles.
Caulk is used between the bottom row of tiles and a bathtub since the bath sits on the floor and the tiles are mounted to the wall Usually, the gap between the tiles and a bathtub will move a lot since the weight of the water (and the bather) will cause the bathtub to move. Clean out the old gap, and use some sort of backer rod or tape so that the caulk only adheres to the tub and the tiles. You want it to be able to stretch, and if it sticks at the back it will be more likely to pull away from the tiles or the tub.
I’m not sure about the shower. I’d grout the walls, and I’d be tempted to replace the bottom gap with whatever was there in the first place unless it had failed completely.
As someone who hates bathroom cleaning with a passion, I love the plastic panel surround in my bathtub/shower (vs. the tile/grout in my parent’s place).
What’s the difference in grout/caulk when it comes to mildew?
You can scrub grout without tearing it up.
Well if it didn’t get mildewy, I wouldn’t have to scrub it. 