Mosaic Tiles in the Bathroom: Choosing and Using Them

What counts as a mosaic

A mosaic tile is a small tile, most often 50mm or less across (some strip formats are longer), supplied on sheets roughly 300mm square. The sheet is held together by a mesh or paper backing so hundreds of pieces can be laid at once. Sizes run from tiny squares to larger hexagons and "finger" strips, and the category covers porcelain, glazed ceramic, glass and natural stone.

Mosaics have been in bathrooms for a long time. Small white hexagons with a black border were a standard floor in early twentieth-century houses, and the look is back in both period restorations and new bathrooms. They are also the most practical tile for certain jobs, which is the better reason to consider them.

Where mosaics work best

Shower floors. This is the strongest case. A shower floor falls toward the waste, and in a hobless shower it can fall in more than one direction. Large tiles cannot follow those changing planes without being cut into envelope shapes or showing uneven edges. Small tiles simply follow the screed. The many grout joints also give more grip for wet feet.

Shower niches and recesses. Mosaics wrap into shallow returns and around small openings more neatly than a large tile that needs fiddly cuts.

Curved or uneven surfaces. A curved wall, a rounded hob or a slightly wavy old wall is easier to cover with small pieces.

Feature panels. A mosaic band behind the vanity, on the shower back wall or across one end of the room adds texture without covering every surface.

Small rooms with a period look. A hexagon or basketweave floor suits a Victorian or Federation bathroom and makes a small floor look deliberate.

Where they are less suitable

• Large open floors, where the cost of laying, the amount of grout and the busy look may outweigh the benefit.
• Every wall in a small room, which can feel busy. Mosaics usually look best with a plainer tile alongside.
• Areas with heavy splashing of dyes or oils, where light grout will stain unless it is a high-performance type.

Materials compared

Porcelain. Dense, low water absorption, hard-wearing and available in floor-rated, slip-resistant finishes. The practical default for a shower floor.

Glazed ceramic. Good on walls, with a wide range of colours. Check the rating before using it on a floor.

Glass. Reflective and colourful, and good for splashbacks, niches and feature walls. Glass mosaics need a white or specified adhesive, because a grey adhesive shows through, and they need careful cutting. Most are not intended for floors.

Natural stone (marble and similar). Warm and traditional, with natural variation from piece to piece. Stone is porous and softer than porcelain, so it usually needs sealing and a pH-neutral cleaner, and it can etch with acidic products.

Recycled or mixed-material blends. These exist, but check the rating and care instructions for each product.

Shapes and patterns

• Hexagon. From small period-style pieces to larger modern ones. Suits floors and walls.
• Square. The simplest mosaic, often in a grid or a blend of shades.
• Penny round. Small circles with wide grout joints between them. A strong retro look, but a lot of grout.
• Mini herringbone and chevron. A small-scale version of the pattern, on sheets, without the set-out work of full-size tiles.
• Finger or stick mosaics. Thin strips laid vertically or horizontally, often on a feature wall.
• Fish scale or fan. Decorative and best kept to a small area.
• Basketweave. Rectangles and small squares in a woven pattern, a classic period floor.

Grout: the part that decides whether you like it in five years

A mosaic floor has many times more grout than a large-format floor. That makes grout choice important:

• Colour. A grout a shade darker than the tile, or a mid-grey, hides everyday marks far better than pure white on a floor.
• Type. Standard cement-based grout works, but it is porous. Epoxy or high-performance grouts resist staining and mould better and are often chosen for shower floors. They are harder to apply cleanly, so an experienced tiler matters.
• Sealing. Cement-based grout on a floor is often sealed. Ask your tiler what the chosen grout needs.
• Movement joints. Internal corners, the floor-to-wall junction and changes of plane get flexible sealant, not grout.

Getting the laying right

The substrate must be flat and waterproofed. Mosaics follow whatever is beneath them, including humps and hollows. In a wet area they go on only after the waterproofing membrane has cured, with an adhesive compatible with that membrane. Waterproofing requirements for wet areas are set out in the building code and the relevant Australian Standard; your licensed builder or waterproofer should confirm what applies to your room.

Hide the sheet lines. The most common flaw in a mosaic is a visible grid where sheets meet. A good tiler spaces sheets so the joints between them match the joints within them, and shuffles sheets from several boxes where colours vary.

Plan the cuts at the waste. A linear drain or a square centre waste should sit on a clean line of tiles. Tile-insert grates let the mosaic continue across the drain for a seamless look.

Clean as you go. Adhesive squeezing up through the joints must be removed before it sets, or it will show through the grout.

Slip resistance

For any bathroom floor, and especially inside the shower, ask for the slip rating of the mosaic you are considering. Australian slip ratings are tested under a national standard, and a wet shower floor generally calls for a higher rating than a dry area. If you are unsure which rating suits your room, check with your builder or tiler before ordering. Mosaics start with an advantage here because of the many grout joints, but a polished glass or stone surface can still be slippery when wet.

Ordering and spares

Mosaic sheets are sold by the square metre or by the sheet. Allow around 10 per cent extra for cuts, breakage and colour blending, and keep a spare sheet or two. Individual pieces can be cut out of a sheet later to repair a damaged patch, which is far easier if the replacement comes from the same batch.

Next steps

Mosaics are usually one part of a wider tiling plan. See bathroom tiling for floors, walls and set-out, and waterproofing for what goes on beneath a shower floor. The renovation cost guide explains the factors that shape a bathroom price. If you're in Sydney's Inner West, we can look at the room and quote it.