· by Michael Blair, Nashville's Tile and Stone
Discolored grout makes a sound bathroom look finished. Replacing it is inexpensive and effective, provided the tile and the waterproofing beneath are actually intact.
When does regrouting work?
Tiles firmly bonded, no hollow sounds when tapped, no movement, and no evidence of water getting behind. Discoloration, staining and surface crumbling of grout alone are all fixable.
The result is dramatic for the cost, particularly in a shower.
When is regrouting not enough?
Hollow-sounding or loose tiles, grout that keeps failing in the same place, damp or soft board behind the tile, or a shower that has been leaking.
Regrouting over a failing waterproofing layer seals in a problem that is already causing damage behind.
- Tap every tile — hollow means debonded
- Check for soft board at the base of a shower wall
- Recurring failure in one area means water behind
- Corners get silicone, not grout, on the way back
- Color-matched grout rarely matches exactly
How it is done
Rake out to a consistent depth with a grout removal tool, clean thoroughly, then regrout and finish. The raking is most of the work and it is where tile edges get chipped by the impatient.
Take the opportunity to replace corner joints with silicone rather than grout while you are there.
Color
Matching existing grout exactly is difficult, since the original has aged. Regrouting a whole wall or floor gives a better result than patching a section.
Deliberately changing the color is often the better decision, since a slightly different match reads as a repair.
FAQ
Regrouting or Starting Again With the Tile — questions
How do I know if regrouting is enough?
Tap every tile — a hollow sound means it has debonded and regrouting will not hold it. Check for soft or damp board at the base of shower walls. If grout keeps failing in the same spot, water is getting behind, and regrouting seals in a problem rather than fixing it.
Can I regrout just one area?
You can, and matching the color is the difficulty — existing grout has aged and new grout will not match, so a patch reads as a repair. Regrouting a whole wall or floor gives a far better result, and deliberately changing color is often better than a near miss.
Should corners be regrouted?
They should be siliconed rather than grouted. Inside corners and changes of plane move, and rigid grout cracks there within a year. Regrouting is a good opportunity to correct that detail, which is one of the most common errors in the original installation.
Can you regrout over old grout?
No, the old grout comes out first. It is raked out to a consistent depth with a grout removal tool, the joints are cleaned, and only then does the new grout go in. The raking is most of the job, and rushing it is how tile edges get chipped. Corner joints come back as silicone.