Cracked, Missing or Stained Grout?
Grout can discolor from use, crack from movement or fall out where joints have failed. Cleaning may improve staining, but a missing or cracked joint needs a repair approach.
Repeated cracking can point to tile or substrate movement. Regrouting the same joint without understanding that movement may only create another short-lived repair.
Remove Failed Material Without Damaging Tile
Loose grout should be removed far enough to create a clean joint for new material. The surrounding tile edges need to be protected during that process.
If tiles are loose, hollow or cracked, Shower Tile Installation & Repair or general Tile Repair may be more appropriate. Grout should not be used as a structural fix for a moving tile assembly.
Regrout, Cure and Seal Where Appropriate
New grout is packed and finished to suit the existing joint profile, then allowed to cure according to the product requirements.
Color matching older grout can be imperfect because age, cleaners and moisture change appearance over time. Sealing may be appropriate for some grout systems but should follow the material instructions rather than be assumed universally.