Why Did My Shower Tile Crack?

Seven cracked tiles in one shower wall. That was the job in Taylors this week — and the answer to why it happened is the same answer for most cracked shower tile.

Cracked tile comes from one of two directions

Either improper installation and materials selection, or thermal expansion and movement of the shower itself.

That second one catches people out. A shower isn’t a static object. It gets hot, it gets cold, it gets wet and dries out, and the house around it moves. All of that has to go somewhere.

Where it has to go

Tile is hard and it doesn’t compress. So when a shower expands, that movement needs somewhere to give — and that somewhere is the changes of plane. The corners. Where wall meets wall, where wall meets floor, where wall meets ceiling.

ANSI specifications require silicone at the changes of plane, not grout. Silicone flexes. Grout doesn’t. That soft joint is what absorbs what the shower does all day.

Here’s the part that surprises people: tile set tight against tile across a wall is perfectly acceptable. Tight joints are not the problem.

What you cannot do is butt tile directly into tile at a change of plane. And that is exactly what had been done here.

With the tile pressed tight into the corner, there was no room to install the caulk properly. Whatever was in that joint was there to look right, not to work — visual, not functional.

So the corner couldn’t move. The expansion had nowhere to go, and it went into the tile. Seven of them cracked.

This wasn’t a caulk failure or a grout failure. It was poor installation method — the joint that was supposed to absorb the movement had never been left room to exist.

Precision tile removal

Behind the tile is the waterproofing — the only reason the wall behind it isn’t rotting. It damages easily during removal, and once it does it has to be repaired or replaced. We repair where we can, because it saves you money. We don’t when it would leave you with a compromised shower.

This shower was built with cement board and a roll-on waterproofing. The tile came out carefully and deliberately, working to avoid damaging what was underneath. Then the backer board was cleaned up so the repair went onto a sound surface instead of old adhesive.

Preserving intact waterproofing

This is the step that decides whether a repair lasts.

The waterproofing around the repair is still intact and still working. The vulnerable point is the seam — where the untouched waterproofing meets the patch. Leave that seam open and you’ve built a path for water to get behind everything you just fixed.

So a waterproof sealant runs along the perimeter of the untouched tile first, sealing in the waterproofing that’s still doing its job.

On this shower we then used a liquid waterproof membrane, brushed on per the manufacturer’s specifications at the proper thickness. A membrane is one way to waterproof, not the only way — what’s right depends on how the shower was built and what we find when it’s open.

Hand fitting of the tiles

Because the original tile was butted tight, a replacement of the same nominal size wouldn’t go into the gap.

Tile varies piece to piece — it’s a fired product, and no two come out of the box identical. So we hand-polished the outside edges of the new tiles with a diamond grit pad until they matched, then set and grouted them.

Two days, start to finish. Standing in the shower now, you can’t tell which seven they were.

If you have shower tiles that need repair

This is what we specialize in. Shower tile repair is its own discipline. Most of the job is behind the tile — the waterproofing, the seam, the reason it failed in the first place. Get that part wrong and the repair comes back.

We identify the point of failure and recommend a course of action that fits your needs and budget. Sometimes that is a handful of tiles. Sometimes what is behind them means something bigger, and we will tell you that straight rather than sell you a repair that will not hold.

Cracked or loose tile in a shower in Greenville or the surrounding Upstate — call (864) 747-9325 for an on-site estimate. You can also see how we build a custom tile shower, or read why expansion joints matter.

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