Shower tile cracks because tile is rigid and the wall behind it moves, gets wet, or was never supported. Heat from a daily shower expands the assembly. Cool-down contracts it. If the membrane was skipped, moisture swells the backer and the tile lets go. A grout crack can be a maintenance job. A crack through the tile face, hollow tile, or a musty smell behind the wall is usually a wet-wall problem. Bath Pro SD refers licensed independent remodelers. This brand does not patch tile.
This is the cause page. Bathroom tile repair in San Diego covers when to patch, regrout, or replace. Do not treat those as the same search.
Tile does not flex. The house does.
Wood studs shrink and swell with humidity. Slab-on-grade houses in Clairemont, Kearny Mesa, and East County still move a little. A shower that is hot twice a day expands and contracts on that frame. Tile has no give. The stress goes into grout first, then into the tile if the bed is thin or the corners were grouted instead of caulked.
Changes of plane (wall-to-wall, wall-to-floor, wall-to-curb) need a flexible joint. Cement grout in those corners is a common install error. The Tile Council of North America publishes movement-joint guidance for tile assemblies. Ask the tile setter which joint they will use at every change of plane. Bath Pro SD does not invent a joint width. Put the product and the detail on the drawing.
How modern showers are built, and where they fail
Older showers were often set in a thick mortar bed over mesh. Many current showers are tile over cement board with thinset. That can be a sound assembly when the board is the right product, the membrane is continuous, and the thinset coverage is full. It fails when someone uses drywall in the wet zone, skips the membrane, or spot-bonds the tile.
Water behind the tile swells paper-faced board and some cement boards if they were never waterproofed. The board grows. The tile cracks or pops. Soft drywall outside the shower, a stain on the ceiling below, or a hollow tap on a tile are the usual tells.
San Diego remodelers see this in 1970s and 1980s fiberglass-to-tile conversions that never opened the wall, and in fast tile jobs that treated grout as waterproofing. Grout is not the waterproofing. The shower waterproofing post is the membrane page.
Heat, thin tile, and holes you drill later
A thin decorative tile, including some glass, moves more with temperature than a dense porcelain. Confirm the tile is rated for a shower wall before it goes up. The box and the manufacturer sheet are the source, not a showroom photo.
Robe hooks, soap dishes, and shower-door fasteners drill through finished tile. That hole is a crack risk and a leak path if it is not detailed. Ask who installs the glass, and whether the blocking and the waterproofing were planned before the tile went up.
A dropped bottle can crack one tile. If the neighbors are solid and dry, that can be a single-tile replacement. If a line of tiles is cracked, treat it as movement or moisture, not bad luck.
Grout crack vs tile crack
A grout crack with a dry, tight field of tile is often a recaulk or regrout. A crack that runs through the tile body, a tile that sounds hollow, or grout that fails in the same place after a repair is the wall talking. Patching the face does not dry the studs.
Do not use vinegar or toilet-bowl acid on cement grout. Acid eats the binder. Use a pH-neutral cleaner the grout manufacturer lists. That care note is about not making a grout crack worse. It is not a repair.
When a San Diego shower needs a rebuild
Open the wall when moisture is in the substrate, when several tiles have let go, or when the pan no longer holds a flood test. A down-to-the-studs shower remodel replaces the failed assembly. A single-tile swap does not.
Coastal humidity in Ocean Beach and La Jolla keeps a damp wall wet longer. Inland hard water does not crack tile by itself. It does highlight failed grout and makes a leak easier to see as scale trails.
Whether a rebuild needs a permit turns on scope, and a trigger list was not confirmed here. For a city address, start with Development Services. Other cities and the county have their own counters. Describe the wall, not only the word tile.
Frequently asked questions
Why is my shower tile cracking after a few years?
The usual causes are movement at corners with no flexible joint, thinset voids, skipped waterproofing, or moisture in the backer. Age of the house is not a diagnosis. Have a licensed tile setter tap the field, check the corners, and look for stains outside the shower.
Can I caulk over a cracked tile?
Caulk can slow water at a hairline for a short time. It does not replace the tile or dry the wall. If the tile is loose or the wall smells musty, stop covering it and have the wet wall inspected.
Does the type of tile matter?
Yes. Dense porcelain generally handles wet walls better than a porous decorative body. Confirm the rating on the manufacturer’s sheet. Stone needs a sealer the supplier specifies. Bath Pro SD does not publish a sealer calendar.
Does Bath Pro SD repair cracked shower tile?
No. Bath Pro SD refers licensed independent remodelers. You contract with that remodeler. Call (858) 400-4896 with the room, the age of the shower, and what you see on the wall.