Can grout be removed and replaced? This is grout between floor tiles and also grout in a glass block wall.
How big a deal is it to do this, cost and time-wise? Can it be done without destroying the tile?
Can it be done? Yes. Can it be done without destroying any of the tiles? Yes. You gotta be very very careful. Be prepared to replace a tile cause accidents happen. If you are just changing the grout because of color i would suggest at grout dyes. Their easy to apply and can be a lot faster without the fear of replacing tiles.