A fictional bathroom, two repair visits, one stubborn line: Maya keeps a spare bag of grout under the sink because the shower corner opens every winter. By the third repair, the bag has started to feel less like maintenance supplies and more like a subscription.
Where the crack lives matters
| Crack pattern | What to investigate |
|---|---|
| Straight line where two planes meet | Missing or unsuitable movement-joint detail. |
| Cracks through the middle of tiles | Movement or a problem in the supporting assembly. |
| Loose tile, staining, or damp finishes nearby | Possible bond failure or water damage requiring a closer assessment. |
Schluter's perimeter movement-joint profiles separate tile from adjoining fixed elements while allowing movement. Depending on the assembly, a specified flexible sealant joint or suitable profile can do that job. The product, joint size, and preparation need to suit the location.
A sealant joint is not the waterproofing system
The visible joint and the waterproofing behind the tile have different jobs. A fresh bead cannot prove that the membrane, corners, or tub connection are intact. If water is appearing outside the shower, the repair needs to find its route rather than merely improve the line you can see.
- Photograph the dry joint before removing material, including the surrounding tiles.
- Ask whether the proposed repair matches the shower system's change-of-plane detail.
- Have old material removed without damaging the waterproofing behind it.
- Follow the sealant's preparation and cure instructions before using the shower again.
The fix still needs looking after
In Maya's imagined repair, the corner receives the right flexible joint after the surrounding assembly is checked. The colour is close rather than invisible, and the joint still needs inspection and eventual renewal. She can live with that. She would prefer not to own grout in bulk.
For the underlying assembly, read the shower waterproofing comparison. If tiles are changing too, check large tile in small bathrooms and the bathroom work sequence.
