Why is there a crackle on the glaze of the hand made tiles?
There are multiple reasons why handmade tiles might have a faint crackle effect or appearance, but it doesn’t mean they’re defective or broken. Here are some of the top reasons why handmade tiles might have crackles.
1. The clay and glaze expand differently
When a tile is fired, the clay body and the glass-like glaze both expand and contract as they heat up and cool down.
If the glaze contracts slightly more than the clay during cooling, tiny hairline cracks develop in the glaze while the clay underneath remains perfectly sound. This creates the beautiful network of fine lines known as crackle.
This is the most common cause of intentional crackle glazing.
2. Traditional handmade production
Unlike factory-produced tiles, handmade tiles vary slightly in:
- Clay composition
- Moisture content
- Thickness
- Firing temperature
- Cooling rate
These subtle variations make every tile unique and contribute to the organic crackle pattern.
Is Tile Crackle a Problem?
The crackle is confined to the glaze, not the tile itself. It does not affect the structural strength of the tile.
For kitchen and bathroom walls, crackle-glazed tiles have been used successfully for centuries. The crackle can be enhanced or diminished with your choice of grout. Grey grout with green tiles will enhance the cracking or black grout with pale colours such as primrose, puro white, Mexican white.
You also have the option of using a sealant before grouting the tiles or using vinegar or grout remover on the tiles afterwards, but we would recommend testing a tile first.
Do crackle-glazed tiles need sealing?
We do not recommend sealing the tiles – unless you are installing a power shower.
Why designers love them
Crackle glazes catch and scatter light differently throughout the day. Instead of reflecting light like a perfectly smooth factory tile, the microscopic network of lines creates subtle depth and movement, making walls feel warmer and more alive like light on water with the gentle permutation in the surface of the tile similar to those on calm water.
For businesses like Milagros, this is one of the qualities that distinguishes genuinely handmade Mexican tiles from mass-produced ceramic tiles: every crackle pattern is unique, so no two tiles are ever exactly alike.
This is exactly what gives Milagros tiles their character—the subtle undulations, slight variations in glaze, and handmade feel that catches the light differently across a wall.
The slight tension between the glaze and the clay causes the tiles to sing when they first arrive with us in the UK. Eventually an equilibrium is found between and the singing ceases.
When you first install your tiles they may also sing or tingle – this is nothing to worry about they are just settling into their new home.
