How to Replace Cracked Tile Grout in a Tub or Shower

How to Replace Cracked Tile Grout in a Tub or Shower. Attend to cracked or crumbling grout joints as soon as they appear. Water getting behind the tiles can ruin the tile job and cause costly  damage. The process described below assumes you need to regrout  the entire area. More often you only have to work on a few damaged  areas. Regardless, it is a four-day job--one day to regrout and  recaulk, two days of curing time and one day for sealing.