The tile market is enormous and the choice is genuinely bewildering. Every showroom has hundreds of options, and the difference between a tile that looks good in a showroom and one that looks good installed in your house is significant but hard to judge from a small sample. This guide sets out the key decisions, the technical requirements that actually matter, and what to avoid.
Porcelain vs Ceramic
The most fundamental distinction. Both are clay-based tiles fired in a kiln, but the differences in composition and firing temperature produce significantly different properties.
Ceramic tiles are fired at lower temperatures and have higher water absorption (typically above 3%). This makes them more suitable for walls and internal floors in dry areas. They're lighter, easier to cut, less expensive, and available in a huge range of finishes and sizes.
Porcelain tiles are fired at higher temperatures (around 1200°C) from a denser clay body, resulting in water absorption below 0.5%. They're harder, denser, and much more durable than ceramic. They're suitable for floors with high traffic, external use (frost-resistant grades), wet rooms, and any application where durability is important. They're heavier, harder to cut (requiring a good quality tile cutter or angle grinder with diamond blade), and generally more expensive.
For bathroom floors and shower enclosures, use porcelain. For bathroom walls that won't get direct water, ceramic is fine and gives more options. For kitchen floors with regular heavy use, porcelain is the right choice. Ceramic floor tiles in a busy kitchen will show wear at the glaze within years.
Tile Formats and What They Do to a Room
The format (size) of a tile is a design decision with significant practical implications.
Small tiles (mosaic, 100x100mm, 150x150mm): Create a traditional or retro aesthetic. More grout lines, which means more maintenance and a busier visual effect. Mosaics on a mesh backing are excellent for curved surfaces and wet room floors. The grout lines in mosaic provide grip underfoot.
Standard tiles (200x300mm wall, 300x300mm floor): The most commonly installed sizes. Relatively quick to lay and easy to cut. Work well in most residential bathrooms. The proportion looks right in rooms under about 6m2.
Large format tiles (600x600mm, 600x1200mm, 800x800mm, 1200x1200mm): Increasingly popular. Fewer grout lines make spaces feel larger and cleaner. However, large format tiles require a very flat and very rigid substrate: any deviation in the floor or wall will be immediately apparent as a lippage (one tile edge higher than the adjacent tile edge). They're heavier, harder to handle, and more waste in rooms with lots of cuts. They also require specialist adhesive applied with a larger notched trowel, and a levelling system during installation is strongly recommended.
Large format tiles in a small bathroom (under 4m2) can look disproportionate. The right tile size is related to the size and proportion of the room, not just the trend.
Slip Ratings for Floor Tiles
Floor tiles are rated for slip resistance. The two main standards used in the UK are R-rating (DIN 51130, a German standard used widely across Europe) and PTV (Pendulum Test Value, under BS 7976). Both measure slip resistance in wet conditions.
For domestic wet areas (bathroom floors, shower enclosures, wet rooms): a minimum R10 or PTV 36 is the recommended standard. R11 or PTV 45+ is better and worth specifying in a shower.
A highly polished porcelain tile (like the large format marble-look tiles that are very popular) will often have a low slip rating when wet. Check the specification before ordering floor tiles for wet areas. Some beautiful tiles are only appropriate for dry floor use, and this is clearly stated in the product data sheet if you look for it.
Grout: The Part Everyone Underspecifies
Grout choice matters more than most people realise and is more often chosen as an afterthought than as a deliberate decision.
Standard cement grout is the default. It's porous when dry and needs sealing in wet areas, otherwise it stains and harbours mould. Modern colour-matched cement grouts are well made and perform well when sealed and maintained.
Epoxy grout is harder, non-porous, more stain resistant, and more chemical resistant. It doesn't need sealing. It's significantly harder to work with: it sets quickly, is sticky, and requires careful application. But in a shower enclosure, on a kitchen splashback, or in any high-traffic floor application, epoxy grout is worth the additional cost and effort. Brands like Mapei Kerapoxy and BAL Micromax are widely used.
Grout joint width is partly determined by tile type. Rectified tiles (factory-edge ground to precise dimensions) can be laid with very narrow joints (2mm or less). Non-rectified tiles have slight dimensional variation and need wider joints (3-5mm) to accommodate this. Using narrow grout joints on non-rectified tiles produces a result that looks irregular and uneven.
Buy more tiles than you need. Order at least 10-15% extra over your measured area for waste, breakages, and cuts. For tiles with a pattern or veining, order 20%. Keeping a box in reserve means that when a tile breaks or needs replacing in five years, you have matching stock. Tile batches change slightly in shade between production runs, and buying more later is not always possible.
Adhesive and Installation
The adhesive choice depends on the tile, the substrate, and the application.
Standard wall adhesive (ready-mixed or powder) is adequate for ceramic wall tiles on plasterboard or cement board in dry to slightly damp conditions.
Rapid-set adhesive for floor tiles and situations where the tile needs to be held in position immediately (large format wall tiles, heavy natural stone).
Flexible adhesive for any application where there may be slight movement: timber floors, underfloor heating, external applications, large format tiles.
The British Standards tile installation standard (BS 5385) specifies which adhesive types are appropriate for which applications. A tiler who references the standard and uses the right adhesive for the substrate and tile combination will produce work that lasts. One who uses standard adhesive for all applications regardless of the substrate will produce work that may look fine initially and fail within a few years.
Natural Stone
Natural stone tiles (marble, limestone, travertine, slate) require specific care both in installation and ongoing maintenance.
Stone is porous and must be sealed before grouting to prevent grout contamination of the surface. Some stones (marble, limestone) are alkali-sensitive and can be damaged by cement-based adhesives if the adhesive contacts the face. Use a flexible adhesive with a low pH for calcium carbonate stones.
Honed finishes show water marks and soap residue more readily than polished finishes. Polished finishes show scratches and traffic wear over time. There is no maintenance-free natural stone option for a bathroom floor.
Travertine has natural voids that need to be filled (grouted or resin-filled) before installation in a wet area, otherwise water sits in the voids and becomes a damp and hygiene problem.