Glazed and unglazed ceramic tiles are made from the same base material but finished in fundamentally different ways. That difference in finish drives almost every practical distinction between them, from slip resistance and stain resistance to maintenance requirements and the range of visual effects available. Understanding both types helps you make the right choice for each surface in your project.

What Is a Glazed Ceramic Tile?

A glazed ceramic tile has a layer of liquid glass applied to the surface of the clay body before the final kiln firing. During firing, this glaze melts and fuses to the tile body, creating a hard, smooth, impervious surface layer. The glaze is where all the colour, pattern and texture of a glazed tile originates. The tile body beneath the glaze is typically a buff, red or off-white clay colour that remains hidden in normal use.

The glaze layer makes the tile surface non-porous. Water, grease, bacteria and staining agents cannot penetrate the tile surface. This is why glazed ceramic tiles are the dominant choice for walls in kitchens and bathrooms and why they are easy to clean and maintain over decades of use.

What Is an Unglazed Ceramic Tile?

An unglazed ceramic tile has no glass layer applied to its surface. The colour and texture you see on the surface of an unglazed tile is the natural colour of the clay body itself, which runs consistently through the full thickness of the tile. This is sometimes called a full-body or through-body tile.

Unglazed ceramic tiles are more porous than their glazed counterparts. Without a glass surface layer, the clay body is exposed and can absorb water, oils and staining agents if left unsealed. For this reason, most unglazed ceramic floor tiles require sealing before use and periodic resealing throughout their life.

Key Differences: A Direct Comparison

Slip Resistance: Where Unglazed Wins

The most significant practical advantage of unglazed ceramic tiles in floor applications is slip resistance. A glazed tile surface, especially when wet, can be slippery depending on the glaze texture. Manufacturers address this by adding texture to the glaze surface, but the underlying smoothness of a glass layer always limits how much grip can be achieved.

Unglazed tiles have a naturally textured clay surface that provides inherent grip. Unglazed ceramic floor tiles typically achieve R10 to R11 slip resistance ratings under DIN 51130 testing, making them appropriate for wet rooms, pool surrounds, commercial kitchens and outdoor applications where glazed tiles would require careful selection to achieve the same safety level.

Wear Resistance: A Critical Distinction for Floors

Glazed ceramic tiles are rated for wear resistance using the PEI (Porcelain Enamel Institute) scale from 0 to 5. The glaze on a glazed tile is a finite layer. On a high-traffic floor, foot traffic and grit gradually wear the glaze surface over years. A PEI 1 or 2 tile is suitable for walls only. A PEI 4 or 5 tile is rated for heavy domestic and commercial floor use.

Unglazed ceramic tiles have no glaze to wear through. Because the colour and texture run through the entire tile body, wear simply exposes more of the same material. This is why unglazed tiles are the material of choice for extremely high-traffic applications such as commercial floors, public spaces and outdoor paving.

Sealing Unglazed Tiles

Every unglazed ceramic tile installed on a floor or in a wet area should be sealed before use. The sealer penetrates the porous clay body and fills the surface pores, dramatically reducing water and stain absorption. Most tile sealers are solvent- or water-based impregnating sealers applied with a cloth or roller. Once dry and cured, the sealer is invisible and does not alter the appearance of the tile. Resealing is typically required every three to five years depending on usage.

Grout joints between unglazed tiles must also be sealed. Cement-based grout is itself porous and will stain if left unsealed in kitchen and bathroom applications.

For a comprehensive view of the ceramic tile options available for your project, visit Precious Marble in Elstow where our team can show you both glazed and unglazed options across a wide range of formats and finishes.

Our ceramic tiles Bedford hub is the starting point for every topic covered in this series, from glazed versus unglazed choices through to installation specification and long-term care.